Resistor Color Code Calculator

Professional, accessible resistor color code calculator. Decode 3/4/5/6-band resistors, compute tolerance and temperature coefficient, or encode a resistance value into color bands. Built for accuracy, speed, and mobile-first usability.

Resistor Color Code Calculator

This professional tool helps engineers, students, and makers decode and encode resistor color bands with absolute clarity. Read 3, 4, 5, or 6-band resistors; compute nominal value, tolerance range, and temperature coefficient. Or input a numeric resistance and get the exact color bands, optimized for mobile and assistive technologies.

Results

Resistor visualization with color bands Dynamic illustration of the resistor body and the selected bands.
Nominal resistance —
Tolerance —
Min → Max —
Temperature coefficient —
Color code —
Shareable URL —

Data Source and Methodology

Primary reference: IEC 60062:2016 (Marking codes for resistors and capacitors), International Electrotechnical Commission, 2016. View IEC 60062.

Secondary reference for preferred numbers: IEC 60063 (Preferred number series for resistors and capacitors). View IEC 60063.

Practical cross-check: Digi-Key — Resistor Color Code Calculator. View resource.

All computations strictly follow the formulas and data provided by these sources.

The Formulas Explained

$$ R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M} $$ where k = 2 for 3/4-band, k = 3 for 5/6-band; d_i are significant digits, and M is the multiplier exponent.

$$ R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big) $$ where τ is the tolerance percentage.

Temperature coefficient (ppm/°C) indicates change per degree: $$ \Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6} $$ where α is the tempco in ppm/°C and ΔT is temperature change in °C.

Glossary of Variables

  • Band 1, 2, 3: Significant digit colors mapping to digits 0–9.
  • Multiplier (M): Power of ten determined by the multiplier band, including gold (10^-1) and silver (10^-2).
  • Tolerance (τ): Allowed percentage deviation; “None” (no band) means ±20%.
  • Temperature coefficient (α): Change per °C in ppm (parts per million) for 6-band resistors.
  • R (Ω): Nominal resistance in ohms.
  • Rmin, Rmax (Ω): Minimum and maximum resistance limits considering tolerance.
  • E-series: Preferred number sets (E12/E24) used to select commercially available values.

How It Works: A Step-by-Step Example

Goal: Decode a 5-band resistor with colors Brown, Black, Green, Red, Brown.

  1. Digits: Brown=1, Black=0, Green=5 → 105.
  2. Multiplier: Red → 10^2, so R = 105 × 10^2 = 10,500 Ω = 10.5 kΩ.
  3. Tolerance: Brown → ±1%. Therefore Rmin = 10.5 kΩ × (1 − 0.01) = 10.395 kΩ; Rmax = 10.5 kΩ × (1 + 0.01) = 10.605 kΩ.
  4. If a 6th band exists, read it as the temperature coefficient (e.g., Red = 50 ppm/°C).

Frequently Asked Questions (FAQ)

How do I read 3, 4, 5, and 6-band resistors?

3-band: 2 digits + multiplier (default ±20%). 4-band: 2 digits + multiplier + tolerance. 5-band: 3 digits + multiplier + tolerance. 6-band: 5-band + temperature coefficient.

Why are gold and silver used?

Gold and silver primarily indicate lower multipliers (×0.1 and ×0.01) and also common tolerances (±5% and ±10%).

What if one band is faded or burned?

Use the remaining bands plus measurement if possible. Compare the computed nominal value to E-series to estimate the missing band. When in doubt, replace with a safe, equal or higher tolerance part and validate in-circuit.

Can the first digit be black (0)?

Practically no for standard coding; the leading digit is typically non-zero. This tool will warn you if an uncommon combination is selected.

How accurate is the temperature coefficient?

The tempco band provides a nominal ppm/°C value per IEC 60062. Real performance depends on the resistor technology (e.g., metal film vs. carbon film) and the operating conditions.

How do E-series impact my selection?

E-series help you select commercially available values. Use E12 (10%) or E24 (5%) snapping to ensure your encoded value matches standard production parts.

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)
\[R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M}\]
R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M}
Formula (extracted LaTeX)
\[R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big)\]
R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big)
Formula (extracted LaTeX)
\[\Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6}\]
\Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6}
Formula (extracted text)
$ R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M} $ where k = 2 for 3/4-band, k = 3 for 5/6-band; d_i are significant digits, and M is the multiplier exponent. $ R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big) $ where τ is the tolerance percentage. Temperature coefficient (ppm/°C) indicates change per degree: $ \Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6} $ where α is the tempco in ppm/°C and ΔT is temperature change in °C.
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

Full original guide (expanded)

CalcDomain
CalcDomain

Resistor Color Code Calculator

This professional tool helps engineers, students, and makers decode and encode resistor color bands with absolute clarity. Read 3, 4, 5, or 6-band resistors; compute nominal value, tolerance range, and temperature coefficient. Or input a numeric resistance and get the exact color bands, optimized for mobile and assistive technologies.

Results

Resistor visualization with color bands Dynamic illustration of the resistor body and the selected bands.
Nominal resistance —
Tolerance —
Min → Max —
Temperature coefficient —
Color code —
Shareable URL —

Data Source and Methodology

Primary reference: IEC 60062:2016 (Marking codes for resistors and capacitors), International Electrotechnical Commission, 2016. View IEC 60062.

Secondary reference for preferred numbers: IEC 60063 (Preferred number series for resistors and capacitors). View IEC 60063.

Practical cross-check: Digi-Key — Resistor Color Code Calculator. View resource.

All computations strictly follow the formulas and data provided by these sources.

The Formulas Explained

$$ R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M} $$ where k = 2 for 3/4-band, k = 3 for 5/6-band; d_i are significant digits, and M is the multiplier exponent.

$$ R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big) $$ where τ is the tolerance percentage.

Temperature coefficient (ppm/°C) indicates change per degree: $$ \Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6} $$ where α is the tempco in ppm/°C and ΔT is temperature change in °C.

Glossary of Variables

  • Band 1, 2, 3: Significant digit colors mapping to digits 0–9.
  • Multiplier (M): Power of ten determined by the multiplier band, including gold (10^-1) and silver (10^-2).
  • Tolerance (τ): Allowed percentage deviation; “None” (no band) means ±20%.
  • Temperature coefficient (α): Change per °C in ppm (parts per million) for 6-band resistors.
  • R (Ω): Nominal resistance in ohms.
  • Rmin, Rmax (Ω): Minimum and maximum resistance limits considering tolerance.
  • E-series: Preferred number sets (E12/E24) used to select commercially available values.

How It Works: A Step-by-Step Example

Goal: Decode a 5-band resistor with colors Brown, Black, Green, Red, Brown.

  1. Digits: Brown=1, Black=0, Green=5 → 105.
  2. Multiplier: Red → 10^2, so R = 105 × 10^2 = 10,500 Ω = 10.5 kΩ.
  3. Tolerance: Brown → ±1%. Therefore Rmin = 10.5 kΩ × (1 − 0.01) = 10.395 kΩ; Rmax = 10.5 kΩ × (1 + 0.01) = 10.605 kΩ.
  4. If a 6th band exists, read it as the temperature coefficient (e.g., Red = 50 ppm/°C).

Frequently Asked Questions (FAQ)

How do I read 3, 4, 5, and 6-band resistors?

3-band: 2 digits + multiplier (default ±20%). 4-band: 2 digits + multiplier + tolerance. 5-band: 3 digits + multiplier + tolerance. 6-band: 5-band + temperature coefficient.

Why are gold and silver used?

Gold and silver primarily indicate lower multipliers (×0.1 and ×0.01) and also common tolerances (±5% and ±10%).

What if one band is faded or burned?

Use the remaining bands plus measurement if possible. Compare the computed nominal value to E-series to estimate the missing band. When in doubt, replace with a safe, equal or higher tolerance part and validate in-circuit.

Can the first digit be black (0)?

Practically no for standard coding; the leading digit is typically non-zero. This tool will warn you if an uncommon combination is selected.

How accurate is the temperature coefficient?

The tempco band provides a nominal ppm/°C value per IEC 60062. Real performance depends on the resistor technology (e.g., metal film vs. carbon film) and the operating conditions.

How do E-series impact my selection?

E-series help you select commercially available values. Use E12 (10%) or E24 (5%) snapping to ensure your encoded value matches standard production parts.

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)
\[R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M}\]
R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M}
Formula (extracted LaTeX)
\[R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big)\]
R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big)
Formula (extracted LaTeX)
\[\Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6}\]
\Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6}
Formula (extracted text)
$ R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M} $ where k = 2 for 3/4-band, k = 3 for 5/6-band; d_i are significant digits, and M is the multiplier exponent. $ R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big) $ where τ is the tolerance percentage. Temperature coefficient (ppm/°C) indicates change per degree: $ \Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6} $ where α is the tempco in ppm/°C and ΔT is temperature change in °C.
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
CalcDomain

Resistor Color Code Calculator

This professional tool helps engineers, students, and makers decode and encode resistor color bands with absolute clarity. Read 3, 4, 5, or 6-band resistors; compute nominal value, tolerance range, and temperature coefficient. Or input a numeric resistance and get the exact color bands, optimized for mobile and assistive technologies.

Results

Resistor visualization with color bands Dynamic illustration of the resistor body and the selected bands.
Nominal resistance —
Tolerance —
Min → Max —
Temperature coefficient —
Color code —
Shareable URL —

Data Source and Methodology

Primary reference: IEC 60062:2016 (Marking codes for resistors and capacitors), International Electrotechnical Commission, 2016. View IEC 60062.

Secondary reference for preferred numbers: IEC 60063 (Preferred number series for resistors and capacitors). View IEC 60063.

Practical cross-check: Digi-Key — Resistor Color Code Calculator. View resource.

All computations strictly follow the formulas and data provided by these sources.

The Formulas Explained

$$ R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M} $$ where k = 2 for 3/4-band, k = 3 for 5/6-band; d_i are significant digits, and M is the multiplier exponent.

$$ R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big) $$ where τ is the tolerance percentage.

Temperature coefficient (ppm/°C) indicates change per degree: $$ \Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6} $$ where α is the tempco in ppm/°C and ΔT is temperature change in °C.

Glossary of Variables

  • Band 1, 2, 3: Significant digit colors mapping to digits 0–9.
  • Multiplier (M): Power of ten determined by the multiplier band, including gold (10^-1) and silver (10^-2).
  • Tolerance (τ): Allowed percentage deviation; “None” (no band) means ±20%.
  • Temperature coefficient (α): Change per °C in ppm (parts per million) for 6-band resistors.
  • R (Ω): Nominal resistance in ohms.
  • Rmin, Rmax (Ω): Minimum and maximum resistance limits considering tolerance.
  • E-series: Preferred number sets (E12/E24) used to select commercially available values.

How It Works: A Step-by-Step Example

Goal: Decode a 5-band resistor with colors Brown, Black, Green, Red, Brown.

  1. Digits: Brown=1, Black=0, Green=5 → 105.
  2. Multiplier: Red → 10^2, so R = 105 × 10^2 = 10,500 Ω = 10.5 kΩ.
  3. Tolerance: Brown → ±1%. Therefore Rmin = 10.5 kΩ × (1 − 0.01) = 10.395 kΩ; Rmax = 10.5 kΩ × (1 + 0.01) = 10.605 kΩ.
  4. If a 6th band exists, read it as the temperature coefficient (e.g., Red = 50 ppm/°C).

Frequently Asked Questions (FAQ)

How do I read 3, 4, 5, and 6-band resistors?

3-band: 2 digits + multiplier (default ±20%). 4-band: 2 digits + multiplier + tolerance. 5-band: 3 digits + multiplier + tolerance. 6-band: 5-band + temperature coefficient.

Why are gold and silver used?

Gold and silver primarily indicate lower multipliers (×0.1 and ×0.01) and also common tolerances (±5% and ±10%).

What if one band is faded or burned?

Use the remaining bands plus measurement if possible. Compare the computed nominal value to E-series to estimate the missing band. When in doubt, replace with a safe, equal or higher tolerance part and validate in-circuit.

Can the first digit be black (0)?

Practically no for standard coding; the leading digit is typically non-zero. This tool will warn you if an uncommon combination is selected.

How accurate is the temperature coefficient?

The tempco band provides a nominal ppm/°C value per IEC 60062. Real performance depends on the resistor technology (e.g., metal film vs. carbon film) and the operating conditions.

How do E-series impact my selection?

E-series help you select commercially available values. Use E12 (10%) or E24 (5%) snapping to ensure your encoded value matches standard production parts.

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)
\[R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M}\]
R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M}
Formula (extracted LaTeX)
\[R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big)\]
R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big)
Formula (extracted LaTeX)
\[\Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6}\]
\Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6}
Formula (extracted text)
$ R = \Big(\sum_{i=1}^{k} d_i \cdot 10^{k-i} \Big)\cdot 10^{M} $ where k = 2 for 3/4-band, k = 3 for 5/6-band; d_i are significant digits, and M is the multiplier exponent. $ R_{\min} = R \cdot \Big(1 - \frac{\tau}{100}\Big), \quad R_{\max} = R \cdot \Big(1 + \frac{\tau}{100}\Big) $ where τ is the tolerance percentage. Temperature coefficient (ppm/°C) indicates change per degree: $ \Delta R \approx R \cdot \alpha \cdot \Delta T \cdot 10^{-6} $ where α is the tempco in ppm/°C and ΔT is temperature change in °C.
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
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).