Liters, Gallons and Cups: How to Convert Volume Units
Enyong Carinton Tegum·
November 9, 2025·
1 min read
Volume is one of the trickiest conversions because the same word means different amounts in different countries. Here's how to avoid the classic mistakes.
The key factors
- 1 liter = 1,000 ml ≈ 0.264 US gallons ≈ 0.22 UK gallons
- 1 US gallon ≈ 3.785 L; 1 UK (imperial) gallon ≈ 4.546 L
- 1 US cup ≈ 240 ml; 1 UK cup ≈ 284 ml
The big trap: US vs UK
A US gallon and a UK gallon differ by nearly 20%, and cups differ too. Always check which standard a recipe or spec uses — getting it wrong can ruin a recipe or miscalculate fuel economy.
Convert any volume
Our free volume converter handles ml, liters, US/UK gallons, pints, cups and more. For recipe-specific conversions (cups to grams), use the cooking measurement converter.
Bottom line
Liters and milliliters are simple; gallons and cups are where it gets dangerous because US and UK versions differ. Confirm the standard, then convert — a converter that lets you pick US or UK removes the guesswork.
