Volume & Capacity Converter

Convert volume and capacity units instantly: liters, milliliters, cubic meters, US gallons, imperial gallons, cups, fluid ounces, tablespoons and more. Includes formulas, tables and classroom notes.

Base unit = liter. All conversions pass through liters to keep rounding consistent. US cup = 236.5882365 mL. Imperial gallon = 4.54609 L. US barrel (oil) = 158.987294928 L.

How this converter works

We use the liter as the “hub.” Any unit you give us is converted to liters, and then liters are converted to the unit you want. This keeps rounding consistent and lets us support both volume (m³, cm³) and capacity (L, mL, gal, cups).

Liters = value × factorToLiter[unit]

Target value = liters ÷ factorToLiter[targetUnit]

Example: 3 US gallons → L → UK pints

3 × 3.785411784 = 11.356235352 L

UK pint factor = 0.56826125 L → 11.356235352 ÷ 0.56826125 ≈ 19.98 UK pints

Volume vs capacity

Volume is geometric (cubic units). Capacity is practical and often depends on the container standard in your country. A 1 L bottle and a 1000 cm³ cube hold the same amount of liquid, but one is described in capacity units, the other in volume units.

Quick table: liters to common kitchen / US units

Liters US cups US fl oz US gallons
0.25 L000
0.5 L000
1 L000
2 L000
3 L000

FAQ

1. Why are my cookbook cups not matching?

Some cookbooks use 240 mL, others 250 mL, but US legal cup is 240 mL and US “customary” cup is ~236.59 mL. We use 236.5882365 mL which is common in converter sites.

2. How do I explain this to students?

Start from 1 L = 1000 mL = 1000 cm³. Then show that 1 m³ = 1000 L. After they’re confident, introduce gallons and cups as just “other names” for fixed volumes.

3. Can I use this for lab work?

Yes, but for high-precision work use the actual glassware tolerance. This tool is great for planning and quick conversions.

Results use the liter hub method so all units flow through a single conversion table. Figures are estimates and may differ from published tables or instruments; consult the original standards for high-precision needs.

Full original guide (expanded)

Classroom notes

  • 1 m³ = 1000 L = 1,000,000 mL.
  • 1 L = 1000 cm³ (because 1 cm³ = 1 mL).
  • US vs UK volumes differ: always state which.
  • For recipes, round to 1–2 decimals.
Formulas

Liters = value × factorToLiter[unit]

Target value = liters ÷ factorToLiter[targetUnit]

Example: 3 US gallons → L → UK pints › 3 × 3.785411784 = 11.356235352 L and 11.356235352 ÷ 0.56826125 ≈ 19.98 UK pints.

Citations

NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures

NIST — SI units — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/owm/metric-si/si-units

Changelog
Version 0.1.0-draft
Last code update: 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 Last updated: 2026-01-19 Version 0.1.0-draft
Version 1.5.0