Convert Cups to US Gallons

About converting Cups to US Gallons

Cups (cup) and US Gallons (gal (US)) are both units of volume, so converting between them is a single multiplication: multiply your Cups figure by 0.0625. Ten Cups comes to 0.625 US Gallons, and a hundred works out at 6.25 US Gallons.

Rule of thumb: going from Cups to US Gallons divides, so the figure always shrinks — it takes about 16 Cups to make a single US Gallon. If your answer came out bigger, you have the conversion the wrong way round.

What is a Cup?

The cup is a cooking unit and nothing else — no scientific or trade use — and it is dangerously ambiguous. The US customary cup in recipes is about 237 mL, the metric cup used in Australia and much of Europe is exactly 250 mL, and the US legal cup that nutrition labels are calculated against is 240 mL, different again from the one in the cookbook. Recipes almost never say which they mean. The problem compounds for dry goods, since a cup measures volume while baking actually depends on mass: how hard you pack the flour changes the answer.

What is an US Gallon?

The US gallon is defined as exactly 231 cubic inches, a figure inherited unchanged from the old English wine gallon. When Britain overhauled its measures in 1824 and adopted a new imperial gallon, the United States simply kept the wine gallon it already had — and that single decision is the root of the entire US-versus-imperial mess that still catches people out today. The US gallon is roughly a fifth smaller than the imperial one, which means American and British fuel-economy figures are not comparable even though both are quoted in miles per gallon.

To put both in perspective: a cup is the measure American recipes count flour in, while a typical American milk jug holds one US gallon.

The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the US Gallons to Cups converter, or browse all Volume converters.