Volume and capacity converter

Volume is where US and British units part ways. A US gallon is 3.785411784 L (231 cubic inches) while an imperial gallon is 4.54609 L, about 20% more; the same goes for pints and fluid ounces. The converter lists US customary, imperial and metric units in separate groups so you pick the right one for your source: a US recipe, a UK fuel-economy figure, a fridge rated in cubic feet or a water tank in cubic metres.

Cups deserve a note. The US customary cup is half a US pint, 236.59 mL; US nutrition labels use a rounded legal cup of 240 mL; Australia, New Zealand, Canada and many metric recipes use a 250 mL cup. Tablespoons are 14.79 mL (US) or 15 mL (metric). For converting cups of flour or sugar to grams, use the cups-to-grams converter, which accounts for each ingredient's density.

Factors come from the exact definitions of the inch and the imperial gallon; see NIST Special Publication 811 (Guide for the Use of the SI), Appendix B.