Siding Calculator

Professional siding calculator to estimate siding squares, boxes, panels, and accessory pieces. Mobile-first, WCAG 2.1 AA accessible, and optimized for Core Web Vitals.

Full original guide (expanded)

Siding Calculator

Estimate siding quantities and waste factors from wall dimensions and panel size.

Inputs

Units
Switch units at any time—values update automatically.
ft
%
ft²
ft²
ft
$

Walls

Openings (windows/doors)

Results

Gross wall area 0.00 ft²
Openings area 0.00 ft²
Net wall area 0.00 ft²
Total with waste 0.00 ft²
Squares needed
0.00
Rounded up: 0
Boxes needed
0.00
Rounded up: 0
Panels needed
—
Rounded up: —
Estimated cost
—
—

Accessories

Starter strip length 0.00 ft
Starter strip pieces 0
J-channel length (around openings) 0.00 ft
J-channel pieces 0
Corner trim pieces 0

Note: Quantities are rounded up to whole pieces for ordering. Results are provided for planning and estimation; verify against manufacturer specs and plans.

Data Source and Methodology

Primary source: Vinyl Siding Institute (VSI), “Vinyl Siding Installation Manual, 11th Edition,” 2020. Direct link: VSI Installation Manual PDF.

Supporting reference for standard geometric area formulas: NIST, “Handbook of Mathematical Functions,” 2010.

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

Gross\ Area:\quad A_{\text{walls}} = \sum \left( w \times h \right) + \sum \left( w_g \times h_g^{\text{wall}} + \tfrac{1}{2} w_g \times h_g^{\text{peak}} \right) Openings\ Area:\quad A_{\text{open}} = \sum \left( w_i \times h_i \right) Net\ Area:\quad A_{\text{net}} = A_{\text{walls}} - A_{\text{open}} Waste\ Applied:\quad A_{\text{tot}} = A_{\text{net}} \times \left(1 + \frac{p_{\text{waste}}}{100}\right) Squares:\quad \text{Squares} = \frac{A_{\text{tot}}}{100\ \text{ft}^2} Boxes:\quad \text{Boxes} = \frac{A_{\text{tot}}}{C_{\text{box}}} Panels:\quad \text{Panels} = \frac{A_{\text{tot}}}{C_{\text{panel}}} Starter\ Pieces:\quad N_{\text{starter}} = \left\lceil \frac{L_{\text{base}}}{L_{\text{piece}}} \right\rceil,\quad J\text{-channel Pieces}: \left\lceil \frac{L_{\text{openings}}}{L_{\text{piece}}} \right\rceil Corner\ Pieces:\quad N_{\text{corner}} = N_{\text{corners}} \times \left\lceil \frac{H_{\text{typ}}}{L_{\text{piece}}} \right\rceil

Glossary of Variables

  • w, h: wall width and height.
  • w_g: gable wall width; h_g^wall: wall height below eave; h_g^peak: additional triangular peak height.
  • A_walls: total wall area before subtracting openings.
  • A_open: total area of all windows and doors.
  • A_net: A_walls − A_open.
  • p_waste: waste percentage; A_tot: net area with waste applied.
  • Squares: A_tot divided by 100 ft².
  • C_box: net coverage per box (area).
  • C_panel: effective coverage per panel (area).
  • L_base: sum of wall base widths (starter strip run).
  • L_openings: sum of perimeters of all openings.
  • L_piece: length of a single accessory piece (e.g., 10 ft).
  • N_corners: number of outside corners; H_typ: typical wall height for corner trims.

Come Funziona: Un Esempio Passo-Passo

Inputs: Two rectangular walls (20 ft × 9 ft and 15 ft × 9 ft), one gable wall (24 ft width, wall height 8 ft, peak height 4 ft). Openings: two windows (3 ft × 4 ft), one door (3 ft × 6.8 ft). Waste 10%. Box coverage 200 ft². Panel coverage 8.3 ft². Piece length 10 ft. Outside corners: 4. Typical height 9 ft.

Compute wall areas: A_rect1 = 20×9 = 180 ft²; A_rect2 = 15×9 = 135 ft²; A_gable = 24×8 + 0.5×24×4 = 192 + 48 = 240 ft². Gross A_walls = 180 + 135 + 240 = 555 ft².

Openings: 2×(3×4) + (3×6.8) = 24 + 20.4 = 44.4 ft². Net A_net = 555 − 44.4 = 510.6 ft².

With waste: A_tot = 510.6 × (1 + 0.10) = 561.66 ft². Squares = 561.66 / 100 = 5.62 → round up to 6 squares. Boxes = 561.66 / 200 = 2.81 → round up to 3 boxes. Panels = 561.66 / 8.3 = 67.67 → round up to 68 panels.

Accessories: L_base = 20 + 15 + 24 = 59 ft → starter pieces = ceil(59/10) = 6. J-channel around openings: perimeter = 2×[(3+4) + (3+6.8)] = 2×(7 + 9.8) = 33.6 ft → pieces = ceil(33.6/10) = 4. Corner trims: 4 × ceil(9/10) = 4.

Frequently Asked Questions (FAQ)

What’s the difference between gross, net, and total with waste?

Gross is all wall area before subtracting openings. Net subtracts windows and doors. Total with waste adds a percentage to cover cuts and off-cuts that aren’t reusable.

Is 200 ft² per box always correct?

No. Coverage varies by profile and brand. This tool lets you set the exact coverage per box—use your product’s datasheet.

How accurate is the panel count?

Panel counts depend on the net exposed coverage per panel. Enter the manufacturer’s effective coverage for the most accurate result.

Should I include sheathing wrap or nails in this estimate?

This calculator focuses on cladding and select accessories. Add fasteners, house wrap, flashing, and sealants per code and manufacturer requirements.

Can I use this for fiber-cement or wood siding?

Yes—the area math is the same. Adjust box/panel coverage and waste to match the specific product and installation pattern.

How do I handle complex elevations?

Break them into smaller walls (add more wall entries) and include special areas separately. Increase waste for heavy detailing.

Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[= (sel, root=document)=>Array.from(root.querySelectorAll(sel)); // Elements const unitRadios =\]
= (sel, root=document)=>Array.from(root.querySelectorAll(sel)); // Elements const unitRadios =
Formula (extracted LaTeX)
\[('.unit-lbl'); const typWallHeightUnit = $('#typWallHeightUnit'); const boxUnit = $('#boxUnit'); const panelUnit = $('#panelUnit'); const pieceLenUnit = $('#pieceLenUnit'); // Results const grossAreaEl = $('#grossArea'); const openingsAreaEl = $('#openingsArea'); const netAreaEl = $('#netArea'); const totalAreaEl = $('#totalArea'); const squaresEl = $('#squares'); const squaresRoundedEl = $('#squaresRounded'); const boxesEl = $('#boxes'); const boxesRoundedEl = $('#boxesRounded'); const panelsEl = $('#panels'); const panelsRoundedEl = $('#panelsRounded'); const costEl = $('#cost'); const costBasisNoteEl = $('#costBasisNote'); const starterLenEl = $('#starterLen'); const starterPiecesEl = $('#starterPieces'); const jLenEl = $('#jLen'); const jPiecesEl = $('#jPieces'); const cornerPiecesEl = $('#cornerPieces'); // Tooltips\]
('.unit-lbl'); const typWallHeightUnit = $('#typWallHeightUnit'); const boxUnit = $('#boxUnit'); const panelUnit = $('#panelUnit'); const pieceLenUnit = $('#pieceLenUnit'); // Results const grossAreaEl = $('#grossArea'); const openingsAreaEl = $('#openingsArea'); const netAreaEl = $('#netArea'); const totalAreaEl = $('#totalArea'); const squaresEl = $('#squares'); const squaresRoundedEl = $('#squaresRounded'); const boxesEl = $('#boxes'); const boxesRoundedEl = $('#boxesRounded'); const panelsEl = $('#panels'); const panelsRoundedEl = $('#panelsRounded'); const costEl = $('#cost'); const costBasisNoteEl = $('#costBasisNote'); const starterLenEl = $('#starterLen'); const starterPiecesEl = $('#starterPieces'); const jLenEl = $('#jLen'); const jPiecesEl = $('#jPieces'); const cornerPiecesEl = $('#cornerPieces'); // Tooltips
Formula (extracted LaTeX)
\[('.rect-only', wallRow); const gableOnly =\]
('.rect-only', wallRow); const gableOnly =
Formula (extracted LaTeX)
\[('.control', wallRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.wall-error', wallRow))); inp.addEventListener('input', recalc); }); $('.remove-wall', wallRow).addEventListener('click', ()=>{ wallRow.remove(); recalc(); }); // Set unit labels\]
('.control', wallRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.wall-error', wallRow))); inp.addEventListener('input', recalc); }); $('.remove-wall', wallRow).addEventListener('click', ()=>{ wallRow.remove(); recalc(); }); // Set unit labels
Formula (extracted LaTeX)
\[('.control', openRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.opening-error', openRow))); inp.addEventListener('input', recalc); }); $('.remove-opening', openRow).addEventListener('click', ()=>{ openRow.remove(); recalc(); });\]
('.control', openRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.opening-error', openRow))); inp.addEventListener('input', recalc); }); $('.remove-opening', openRow).addEventListener('click', ()=>{ openRow.remove(); recalc(); });
Formula (extracted text)
Gross\ Area:\quad A_{\text{walls}} = \sum \left( w \times h \right) + \sum \left( w_g \times h_g^{\text{wall}} + \tfrac{1}{2} w_g \times h_g^{\text{peak}} \right) Openings\ Area:\quad A_{\text{open}} = \sum \left( w_i \times h_i \right) Net\ Area:\quad A_{\text{net}} = A_{\text{walls}} - A_{\text{open}} Waste\ Applied:\quad A_{\text{tot}} = A_{\text{net}} \times \left(1 + \frac{p_{\text{waste}}}{100}\right) Squares:\quad \text{Squares} = \frac{A_{\text{tot}}}{100\ \text{ft}^2} Boxes:\quad \text{Boxes} = \frac{A_{\text{tot}}}{C_{\text{box}}} Panels:\quad \text{Panels} = \frac{A_{\text{tot}}}{C_{\text{panel}}} Starter\ Pieces:\quad N_{\text{starter}} = \left\lceil \frac{L_{\text{base}}}{L_{\text{piece}}} \right\rceil,\quad J\text{-channel Pieces}: \left\lceil \frac{L_{\text{openings}}}{L_{\text{piece}}} \right\rceil Corner\ Pieces:\quad N_{\text{corner}} = N_{\text{corners}} \times \left\lceil \frac{H_{\text{typ}}}{L_{\text{piece}}} \right\rceil
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

Siding Calculator

Estimate siding quantities and waste factors from wall dimensions and panel size.

Inputs

Units
Switch units at any time—values update automatically.
ft
%
ft²
ft²
ft
$

Walls

Openings (windows/doors)

Results

Gross wall area 0.00 ft²
Openings area 0.00 ft²
Net wall area 0.00 ft²
Total with waste 0.00 ft²
Squares needed
0.00
Rounded up: 0
Boxes needed
0.00
Rounded up: 0
Panels needed
—
Rounded up: —
Estimated cost
—
—

Accessories

Starter strip length 0.00 ft
Starter strip pieces 0
J-channel length (around openings) 0.00 ft
J-channel pieces 0
Corner trim pieces 0

Note: Quantities are rounded up to whole pieces for ordering. Results are provided for planning and estimation; verify against manufacturer specs and plans.

Data Source and Methodology

Primary source: Vinyl Siding Institute (VSI), “Vinyl Siding Installation Manual, 11th Edition,” 2020. Direct link: VSI Installation Manual PDF.

Supporting reference for standard geometric area formulas: NIST, “Handbook of Mathematical Functions,” 2010.

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

Gross\ Area:\quad A_{\text{walls}} = \sum \left( w \times h \right) + \sum \left( w_g \times h_g^{\text{wall}} + \tfrac{1}{2} w_g \times h_g^{\text{peak}} \right) Openings\ Area:\quad A_{\text{open}} = \sum \left( w_i \times h_i \right) Net\ Area:\quad A_{\text{net}} = A_{\text{walls}} - A_{\text{open}} Waste\ Applied:\quad A_{\text{tot}} = A_{\text{net}} \times \left(1 + \frac{p_{\text{waste}}}{100}\right) Squares:\quad \text{Squares} = \frac{A_{\text{tot}}}{100\ \text{ft}^2} Boxes:\quad \text{Boxes} = \frac{A_{\text{tot}}}{C_{\text{box}}} Panels:\quad \text{Panels} = \frac{A_{\text{tot}}}{C_{\text{panel}}} Starter\ Pieces:\quad N_{\text{starter}} = \left\lceil \frac{L_{\text{base}}}{L_{\text{piece}}} \right\rceil,\quad J\text{-channel Pieces}: \left\lceil \frac{L_{\text{openings}}}{L_{\text{piece}}} \right\rceil Corner\ Pieces:\quad N_{\text{corner}} = N_{\text{corners}} \times \left\lceil \frac{H_{\text{typ}}}{L_{\text{piece}}} \right\rceil

Glossary of Variables

  • w, h: wall width and height.
  • w_g: gable wall width; h_g^wall: wall height below eave; h_g^peak: additional triangular peak height.
  • A_walls: total wall area before subtracting openings.
  • A_open: total area of all windows and doors.
  • A_net: A_walls − A_open.
  • p_waste: waste percentage; A_tot: net area with waste applied.
  • Squares: A_tot divided by 100 ft².
  • C_box: net coverage per box (area).
  • C_panel: effective coverage per panel (area).
  • L_base: sum of wall base widths (starter strip run).
  • L_openings: sum of perimeters of all openings.
  • L_piece: length of a single accessory piece (e.g., 10 ft).
  • N_corners: number of outside corners; H_typ: typical wall height for corner trims.

Come Funziona: Un Esempio Passo-Passo

Inputs: Two rectangular walls (20 ft × 9 ft and 15 ft × 9 ft), one gable wall (24 ft width, wall height 8 ft, peak height 4 ft). Openings: two windows (3 ft × 4 ft), one door (3 ft × 6.8 ft). Waste 10%. Box coverage 200 ft². Panel coverage 8.3 ft². Piece length 10 ft. Outside corners: 4. Typical height 9 ft.

Compute wall areas: A_rect1 = 20×9 = 180 ft²; A_rect2 = 15×9 = 135 ft²; A_gable = 24×8 + 0.5×24×4 = 192 + 48 = 240 ft². Gross A_walls = 180 + 135 + 240 = 555 ft².

Openings: 2×(3×4) + (3×6.8) = 24 + 20.4 = 44.4 ft². Net A_net = 555 − 44.4 = 510.6 ft².

With waste: A_tot = 510.6 × (1 + 0.10) = 561.66 ft². Squares = 561.66 / 100 = 5.62 → round up to 6 squares. Boxes = 561.66 / 200 = 2.81 → round up to 3 boxes. Panels = 561.66 / 8.3 = 67.67 → round up to 68 panels.

Accessories: L_base = 20 + 15 + 24 = 59 ft → starter pieces = ceil(59/10) = 6. J-channel around openings: perimeter = 2×[(3+4) + (3+6.8)] = 2×(7 + 9.8) = 33.6 ft → pieces = ceil(33.6/10) = 4. Corner trims: 4 × ceil(9/10) = 4.

Frequently Asked Questions (FAQ)

What’s the difference between gross, net, and total with waste?

Gross is all wall area before subtracting openings. Net subtracts windows and doors. Total with waste adds a percentage to cover cuts and off-cuts that aren’t reusable.

Is 200 ft² per box always correct?

No. Coverage varies by profile and brand. This tool lets you set the exact coverage per box—use your product’s datasheet.

How accurate is the panel count?

Panel counts depend on the net exposed coverage per panel. Enter the manufacturer’s effective coverage for the most accurate result.

Should I include sheathing wrap or nails in this estimate?

This calculator focuses on cladding and select accessories. Add fasteners, house wrap, flashing, and sealants per code and manufacturer requirements.

Can I use this for fiber-cement or wood siding?

Yes—the area math is the same. Adjust box/panel coverage and waste to match the specific product and installation pattern.

How do I handle complex elevations?

Break them into smaller walls (add more wall entries) and include special areas separately. Increase waste for heavy detailing.

Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[= (sel, root=document)=>Array.from(root.querySelectorAll(sel)); // Elements const unitRadios =\]
= (sel, root=document)=>Array.from(root.querySelectorAll(sel)); // Elements const unitRadios =
Formula (extracted LaTeX)
\[('.unit-lbl'); const typWallHeightUnit = $('#typWallHeightUnit'); const boxUnit = $('#boxUnit'); const panelUnit = $('#panelUnit'); const pieceLenUnit = $('#pieceLenUnit'); // Results const grossAreaEl = $('#grossArea'); const openingsAreaEl = $('#openingsArea'); const netAreaEl = $('#netArea'); const totalAreaEl = $('#totalArea'); const squaresEl = $('#squares'); const squaresRoundedEl = $('#squaresRounded'); const boxesEl = $('#boxes'); const boxesRoundedEl = $('#boxesRounded'); const panelsEl = $('#panels'); const panelsRoundedEl = $('#panelsRounded'); const costEl = $('#cost'); const costBasisNoteEl = $('#costBasisNote'); const starterLenEl = $('#starterLen'); const starterPiecesEl = $('#starterPieces'); const jLenEl = $('#jLen'); const jPiecesEl = $('#jPieces'); const cornerPiecesEl = $('#cornerPieces'); // Tooltips\]
('.unit-lbl'); const typWallHeightUnit = $('#typWallHeightUnit'); const boxUnit = $('#boxUnit'); const panelUnit = $('#panelUnit'); const pieceLenUnit = $('#pieceLenUnit'); // Results const grossAreaEl = $('#grossArea'); const openingsAreaEl = $('#openingsArea'); const netAreaEl = $('#netArea'); const totalAreaEl = $('#totalArea'); const squaresEl = $('#squares'); const squaresRoundedEl = $('#squaresRounded'); const boxesEl = $('#boxes'); const boxesRoundedEl = $('#boxesRounded'); const panelsEl = $('#panels'); const panelsRoundedEl = $('#panelsRounded'); const costEl = $('#cost'); const costBasisNoteEl = $('#costBasisNote'); const starterLenEl = $('#starterLen'); const starterPiecesEl = $('#starterPieces'); const jLenEl = $('#jLen'); const jPiecesEl = $('#jPieces'); const cornerPiecesEl = $('#cornerPieces'); // Tooltips
Formula (extracted LaTeX)
\[('.rect-only', wallRow); const gableOnly =\]
('.rect-only', wallRow); const gableOnly =
Formula (extracted LaTeX)
\[('.control', wallRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.wall-error', wallRow))); inp.addEventListener('input', recalc); }); $('.remove-wall', wallRow).addEventListener('click', ()=>{ wallRow.remove(); recalc(); }); // Set unit labels\]
('.control', wallRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.wall-error', wallRow))); inp.addEventListener('input', recalc); }); $('.remove-wall', wallRow).addEventListener('click', ()=>{ wallRow.remove(); recalc(); }); // Set unit labels
Formula (extracted LaTeX)
\[('.control', openRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.opening-error', openRow))); inp.addEventListener('input', recalc); }); $('.remove-opening', openRow).addEventListener('click', ()=>{ openRow.remove(); recalc(); });\]
('.control', openRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.opening-error', openRow))); inp.addEventListener('input', recalc); }); $('.remove-opening', openRow).addEventListener('click', ()=>{ openRow.remove(); recalc(); });
Formula (extracted text)
Gross\ Area:\quad A_{\text{walls}} = \sum \left( w \times h \right) + \sum \left( w_g \times h_g^{\text{wall}} + \tfrac{1}{2} w_g \times h_g^{\text{peak}} \right) Openings\ Area:\quad A_{\text{open}} = \sum \left( w_i \times h_i \right) Net\ Area:\quad A_{\text{net}} = A_{\text{walls}} - A_{\text{open}} Waste\ Applied:\quad A_{\text{tot}} = A_{\text{net}} \times \left(1 + \frac{p_{\text{waste}}}{100}\right) Squares:\quad \text{Squares} = \frac{A_{\text{tot}}}{100\ \text{ft}^2} Boxes:\quad \text{Boxes} = \frac{A_{\text{tot}}}{C_{\text{box}}} Panels:\quad \text{Panels} = \frac{A_{\text{tot}}}{C_{\text{panel}}} Starter\ Pieces:\quad N_{\text{starter}} = \left\lceil \frac{L_{\text{base}}}{L_{\text{piece}}} \right\rceil,\quad J\text{-channel Pieces}: \left\lceil \frac{L_{\text{openings}}}{L_{\text{piece}}} \right\rceil Corner\ Pieces:\quad N_{\text{corner}} = N_{\text{corners}} \times \left\lceil \frac{H_{\text{typ}}}{L_{\text{piece}}} \right\rceil
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
Profile · LinkedIn

Siding Calculator

Estimate siding quantities and waste factors from wall dimensions and panel size.

Inputs

Units
Switch units at any time—values update automatically.
ft
%
ft²
ft²
ft
$

Walls

Openings (windows/doors)

Results

Gross wall area 0.00 ft²
Openings area 0.00 ft²
Net wall area 0.00 ft²
Total with waste 0.00 ft²
Squares needed
0.00
Rounded up: 0
Boxes needed
0.00
Rounded up: 0
Panels needed
—
Rounded up: —
Estimated cost
—
—

Accessories

Starter strip length 0.00 ft
Starter strip pieces 0
J-channel length (around openings) 0.00 ft
J-channel pieces 0
Corner trim pieces 0

Note: Quantities are rounded up to whole pieces for ordering. Results are provided for planning and estimation; verify against manufacturer specs and plans.

Data Source and Methodology

Primary source: Vinyl Siding Institute (VSI), “Vinyl Siding Installation Manual, 11th Edition,” 2020. Direct link: VSI Installation Manual PDF.

Supporting reference for standard geometric area formulas: NIST, “Handbook of Mathematical Functions,” 2010.

Tutti i calcoli si basano rigorosamente sulle formule e sui dati forniti da questa fonte.

The Formula Explained

Gross\ Area:\quad A_{\text{walls}} = \sum \left( w \times h \right) + \sum \left( w_g \times h_g^{\text{wall}} + \tfrac{1}{2} w_g \times h_g^{\text{peak}} \right) Openings\ Area:\quad A_{\text{open}} = \sum \left( w_i \times h_i \right) Net\ Area:\quad A_{\text{net}} = A_{\text{walls}} - A_{\text{open}} Waste\ Applied:\quad A_{\text{tot}} = A_{\text{net}} \times \left(1 + \frac{p_{\text{waste}}}{100}\right) Squares:\quad \text{Squares} = \frac{A_{\text{tot}}}{100\ \text{ft}^2} Boxes:\quad \text{Boxes} = \frac{A_{\text{tot}}}{C_{\text{box}}} Panels:\quad \text{Panels} = \frac{A_{\text{tot}}}{C_{\text{panel}}} Starter\ Pieces:\quad N_{\text{starter}} = \left\lceil \frac{L_{\text{base}}}{L_{\text{piece}}} \right\rceil,\quad J\text{-channel Pieces}: \left\lceil \frac{L_{\text{openings}}}{L_{\text{piece}}} \right\rceil Corner\ Pieces:\quad N_{\text{corner}} = N_{\text{corners}} \times \left\lceil \frac{H_{\text{typ}}}{L_{\text{piece}}} \right\rceil

Glossary of Variables

  • w, h: wall width and height.
  • w_g: gable wall width; h_g^wall: wall height below eave; h_g^peak: additional triangular peak height.
  • A_walls: total wall area before subtracting openings.
  • A_open: total area of all windows and doors.
  • A_net: A_walls − A_open.
  • p_waste: waste percentage; A_tot: net area with waste applied.
  • Squares: A_tot divided by 100 ft².
  • C_box: net coverage per box (area).
  • C_panel: effective coverage per panel (area).
  • L_base: sum of wall base widths (starter strip run).
  • L_openings: sum of perimeters of all openings.
  • L_piece: length of a single accessory piece (e.g., 10 ft).
  • N_corners: number of outside corners; H_typ: typical wall height for corner trims.

Come Funziona: Un Esempio Passo-Passo

Inputs: Two rectangular walls (20 ft × 9 ft and 15 ft × 9 ft), one gable wall (24 ft width, wall height 8 ft, peak height 4 ft). Openings: two windows (3 ft × 4 ft), one door (3 ft × 6.8 ft). Waste 10%. Box coverage 200 ft². Panel coverage 8.3 ft². Piece length 10 ft. Outside corners: 4. Typical height 9 ft.

Compute wall areas: A_rect1 = 20×9 = 180 ft²; A_rect2 = 15×9 = 135 ft²; A_gable = 24×8 + 0.5×24×4 = 192 + 48 = 240 ft². Gross A_walls = 180 + 135 + 240 = 555 ft².

Openings: 2×(3×4) + (3×6.8) = 24 + 20.4 = 44.4 ft². Net A_net = 555 − 44.4 = 510.6 ft².

With waste: A_tot = 510.6 × (1 + 0.10) = 561.66 ft². Squares = 561.66 / 100 = 5.62 → round up to 6 squares. Boxes = 561.66 / 200 = 2.81 → round up to 3 boxes. Panels = 561.66 / 8.3 = 67.67 → round up to 68 panels.

Accessories: L_base = 20 + 15 + 24 = 59 ft → starter pieces = ceil(59/10) = 6. J-channel around openings: perimeter = 2×[(3+4) + (3+6.8)] = 2×(7 + 9.8) = 33.6 ft → pieces = ceil(33.6/10) = 4. Corner trims: 4 × ceil(9/10) = 4.

Frequently Asked Questions (FAQ)

What’s the difference between gross, net, and total with waste?

Gross is all wall area before subtracting openings. Net subtracts windows and doors. Total with waste adds a percentage to cover cuts and off-cuts that aren’t reusable.

Is 200 ft² per box always correct?

No. Coverage varies by profile and brand. This tool lets you set the exact coverage per box—use your product’s datasheet.

How accurate is the panel count?

Panel counts depend on the net exposed coverage per panel. Enter the manufacturer’s effective coverage for the most accurate result.

Should I include sheathing wrap or nails in this estimate?

This calculator focuses on cladding and select accessories. Add fasteners, house wrap, flashing, and sealants per code and manufacturer requirements.

Can I use this for fiber-cement or wood siding?

Yes—the area math is the same. Adjust box/panel coverage and waste to match the specific product and installation pattern.

How do I handle complex elevations?

Break them into smaller walls (add more wall entries) and include special areas separately. Increase waste for heavy detailing.

Audit: Complete
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
\[','\]
','
Formula (extracted LaTeX)
\[= (sel, root=document)=>Array.from(root.querySelectorAll(sel)); // Elements const unitRadios =\]
= (sel, root=document)=>Array.from(root.querySelectorAll(sel)); // Elements const unitRadios =
Formula (extracted LaTeX)
\[('.unit-lbl'); const typWallHeightUnit = $('#typWallHeightUnit'); const boxUnit = $('#boxUnit'); const panelUnit = $('#panelUnit'); const pieceLenUnit = $('#pieceLenUnit'); // Results const grossAreaEl = $('#grossArea'); const openingsAreaEl = $('#openingsArea'); const netAreaEl = $('#netArea'); const totalAreaEl = $('#totalArea'); const squaresEl = $('#squares'); const squaresRoundedEl = $('#squaresRounded'); const boxesEl = $('#boxes'); const boxesRoundedEl = $('#boxesRounded'); const panelsEl = $('#panels'); const panelsRoundedEl = $('#panelsRounded'); const costEl = $('#cost'); const costBasisNoteEl = $('#costBasisNote'); const starterLenEl = $('#starterLen'); const starterPiecesEl = $('#starterPieces'); const jLenEl = $('#jLen'); const jPiecesEl = $('#jPieces'); const cornerPiecesEl = $('#cornerPieces'); // Tooltips\]
('.unit-lbl'); const typWallHeightUnit = $('#typWallHeightUnit'); const boxUnit = $('#boxUnit'); const panelUnit = $('#panelUnit'); const pieceLenUnit = $('#pieceLenUnit'); // Results const grossAreaEl = $('#grossArea'); const openingsAreaEl = $('#openingsArea'); const netAreaEl = $('#netArea'); const totalAreaEl = $('#totalArea'); const squaresEl = $('#squares'); const squaresRoundedEl = $('#squaresRounded'); const boxesEl = $('#boxes'); const boxesRoundedEl = $('#boxesRounded'); const panelsEl = $('#panels'); const panelsRoundedEl = $('#panelsRounded'); const costEl = $('#cost'); const costBasisNoteEl = $('#costBasisNote'); const starterLenEl = $('#starterLen'); const starterPiecesEl = $('#starterPieces'); const jLenEl = $('#jLen'); const jPiecesEl = $('#jPieces'); const cornerPiecesEl = $('#cornerPieces'); // Tooltips
Formula (extracted LaTeX)
\[('.rect-only', wallRow); const gableOnly =\]
('.rect-only', wallRow); const gableOnly =
Formula (extracted LaTeX)
\[('.control', wallRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.wall-error', wallRow))); inp.addEventListener('input', recalc); }); $('.remove-wall', wallRow).addEventListener('click', ()=>{ wallRow.remove(); recalc(); }); // Set unit labels\]
('.control', wallRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.wall-error', wallRow))); inp.addEventListener('input', recalc); }); $('.remove-wall', wallRow).addEventListener('click', ()=>{ wallRow.remove(); recalc(); }); // Set unit labels
Formula (extracted LaTeX)
\[('.control', openRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.opening-error', openRow))); inp.addEventListener('input', recalc); }); $('.remove-opening', openRow).addEventListener('click', ()=>{ openRow.remove(); recalc(); });\]
('.control', openRow).forEach(inp=>{ inp.addEventListener('blur', ()=> validateNumber(inp, 0, null, $('.opening-error', openRow))); inp.addEventListener('input', recalc); }); $('.remove-opening', openRow).addEventListener('click', ()=>{ openRow.remove(); recalc(); });
Formula (extracted text)
Gross\ Area:\quad A_{\text{walls}} = \sum \left( w \times h \right) + \sum \left( w_g \times h_g^{\text{wall}} + \tfrac{1}{2} w_g \times h_g^{\text{peak}} \right) Openings\ Area:\quad A_{\text{open}} = \sum \left( w_i \times h_i \right) Net\ Area:\quad A_{\text{net}} = A_{\text{walls}} - A_{\text{open}} Waste\ Applied:\quad A_{\text{tot}} = A_{\text{net}} \times \left(1 + \frac{p_{\text{waste}}}{100}\right) Squares:\quad \text{Squares} = \frac{A_{\text{tot}}}{100\ \text{ft}^2} Boxes:\quad \text{Boxes} = \frac{A_{\text{tot}}}{C_{\text{box}}} Panels:\quad \text{Panels} = \frac{A_{\text{tot}}}{C_{\text{panel}}} Starter\ Pieces:\quad N_{\text{starter}} = \left\lceil \frac{L_{\text{base}}}{L_{\text{piece}}} \right\rceil,\quad J\text{-channel Pieces}: \left\lceil \frac{L_{\text{openings}}}{L_{\text{piece}}} \right\rceil Corner\ Pieces:\quad N_{\text{corner}} = N_{\text{corners}} \times \left\lceil \frac{H_{\text{typ}}}{L_{\text{piece}}} \right\rceil
Variables and units
  • No variables provided in audit spec.
Sources (authoritative):
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
  • Initial audit spec draft generated from HTML extraction (review required).
  • Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
  • Confirm sources are authoritative and relevant to the calculator methodology.
Verified by Ugo Candido on 2026-01-19
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Formulas

(Formulas preserved from original page content, if present.)

Version 0.1.0-draft
Citations

Add authoritative sources relevant to this calculator (standards bodies, manuals, official docs).

Changelog
  • 0.1.0-draft — 2026-01-19: Initial draft (review required).