Volume Converter

How this volume conversion is calculated

Every unit is a number of milliliters. The result is amount × (milliliters in the "from" unit) ÷ (milliliters in the "to" unit), rounded to six decimal places. The US factors are the sizes implied by defining the US gallon as 231 cubic inches and the inch as 0.0254 meters. One cubic inch is 16.387064 milliliters, and 231 × 16.387064 = 3785.411784 milliliters, which is the gallon factor in the code. The smaller US units are exact divisions of that gallon: fluid ounce = gallon ÷ 128 = 29.5735295625 mL, cup = 8 fluid ounces = 236.5882365 mL, pint = 2 cups = 473.176473 mL, quart = 2 pints = 946.352946 mL, tablespoon = 3 teaspoons, teaspoon = gallon ÷ 768 = 4.92892159375 mL. NIST Special Publication 811 lists these US customary volume factors.

The imperial gallon in the code is 4546.09 milliliters, which is the UK definition of exactly 4.54609 litres. The imperial pint is that gallon divided by 8, 568.26125 mL. The imperial fluid ounce is the gallon divided by 160, 28.4130625 mL. The menu has no imperial cup, no imperial quart, no imperial teaspoon, and no cubic meter. A recipe that says "cup" without a country is not answered by guessing. The cooking converter is the page that also knows kitchen spoons and a short list of ingredient densities. This page never converts milliliters of flour into grams.

Worked examples

Example 1: One US gallon to liters

1 × 3785.411784 ÷ 1000 = 3.785411784 liters, which displays as 3.785412. Five US gallons display as 18.927059 liters. The extra digit past 3.785 is the six-place rounding of the exact 231-cubic-inch gallon, not a second definition.

Example 2: One imperial gallon beside one US gallon

1 imperial gallon displays as 4.54609 liters. The same imperial gallon converted to US gallons displays as 1.20095. The other direction, 1 US gallon to imperial gallons, displays as 0.832674. The two gallons share a name and not a size. A fuel figure, a paint can, or a recipe that says "gallon" has to say which one, because this menu will not infer it from the rest of the sentence.

Example 3: Two US cups, one US pint, sixteen US fluid ounces

2 US cups display as 473.176473 milliliters. 1 US pint displays as the same 473.176473 milliliters, because the pint factor is exactly two cup factors. 16 US fluid ounces also land on 473.176473 milliliters. If a conversion among those three does not come back to that number, the unit you picked is not the US one. One liter to US fluid ounces displays as 33.814023.

When to use this

Use it for a capacity: a jug, a fuel can, a paint can, an aquarium, a bottle labeled in milliliters that you want in US fluid ounces. Use the Cooking Measurement Converter when the amount is a spoon or a cup in a recipe, especially if the other side is grams of flour, sugar, or butter. Those densities are not on this page. Use the Concrete Volume Calculator for a slab in cubic yards. Concrete is not a gallon conversion. Use the Fuel Economy Comparison when you already have miles per gallon and a price per gallon. That page divides miles by the MPG you type. It does not convert a US gallon into an imperial gallon. If one car's figure was published per imperial gallon and the other's per US gallon, convert the volume first so both MPG numbers mean the same gallon, then compare.

What "about 20 percent" gets wrong if you need the panel

An imperial gallon is larger than a US gallon. The panel's factor, not a rounded percent, is the conversion: 1 imperial gallon displays as 1.20095 US gallons. Using 1.2 as a mental shortcut is close and will not match six decimal places. The cooking tool uses the same US cup, pint, quart, and gallon milliliter factors this page uses, and the same imperial fluid ounce, pint, and gallon. It also has imperial teaspoons and tablespoons that this menu does not. If you need those spoons, use the cooking page. If you need the six-decimal display of a gallon, stay here.

Common mistakes

• Treating the two gallons as one unit. 1 US gallon displays as 3.785412 liters. 1 imperial gallon displays as 4.54609 liters.
• Looking for a cubic meter or an imperial cup. They are not in the menu. A cubic meter is 1,000 liters, which you can type as 1000 liters. An imperial cup is not defined on this page.
• Converting flour cups to grams here. This tool returns milliliters of volume. Weight of a cup depends on the ingredient, and that table lives on the cooking converter.
• Using a fluid ounce as a weight ounce. The fluid ounce entries are volume. Mass ounces are on the Weight Converter. They are not equal except in special cases this page does not assume.
• Rounding to 3.785 liters and then scaling a large tank. Five US gallons display as 18.927059 liters. Five times 3.785 is 18.925, which is already off the panel.
• Comparing MPG across gallon systems without converting. The fuel tool multiplies by the price you type and divides by the MPG you type. It does not know which gallon those miles were measured against.

Limitations

Twelve units, milliliters as the only base, six decimal places on output. No mass, no density, no temperature correction, no imperial spoon, no cubic meter, no cubic foot, and no dry-versus-liquid pint switch. Thermal expansion is not applied. A hot liquid and a cold liquid with the same label volume stay the same number. Package claims that round a cup to 240 mL or 250 mL will not match the 236.5882365 mL US cup used here. Type milliliters when the recipe already did.

A tablespoon and a liter, at six decimals

One US tablespoon displays as 14.786765 milliliters. That is six-decimal rounding of 14.78676478125, which is three teaspoons, and a teaspoon is the US gallon divided by 768. One liter displays as 33.814023 US fluid ounces. A label that says 33.8 fl oz has rounded further than this page. The page still will not turn that liter into grams. Density is not one of the factors.

FAQ

Which gallon is 3.785412 liters?

The US gallon. The factor is 3785.411784 milliliters, from 231 cubic inches, and the panel rounds the one-gallon result to 3.785412 liters. The imperial gallon displays as 4.54609 liters.

Why is a US cup 236.5882365 milliliters and not 240 or 250?

Because this page defines it as eight US fluid ounces, and the fluid ounce is the US gallon divided by 128. A 250 mL metric cup and a rounded 240 mL cup are different measures. They are not menu entries. Enter 250 milliliters if that is what the recipe says.

Are two US cups exactly one US pint here?

Yes. Both display as 473.176473 milliliters. Sixteen US fluid ounces display as the same number. The factors were built so those identities hold before rounding.

Can I convert a paint can and then estimate the room?

You can convert the can's volume into liters or US gallons here. How many gallons the walls need is the Paint Coverage Calculator, which starts from area and a coverage rate, not from this converter.

Does the cooking converter use the same cup?

Yes for US volume units and for the imperial fluid ounce, pint, and gallon. The cooking page also has ingredient densities and imperial spoons. This page does not. The baking pan conversion chart uses this page's US cup, 236.5882365 milliliters, when it turns a stated pan depth into cups.

Will heating the liquid change the result?

Not on this page. The conversion is the labeled volume times a fixed factor. It does not apply a thermal-expansion coefficient.

What should I do with a UK tablespoon?

It is not in this menu. Use the Cooking Measurement Converter, which has an imperial tablespoon, or convert from milliliters if you already know the milliliter amount the recipe intends.

Related calculators

• Cooking Measurement Converter for spoons, cups, and grams of a listed ingredient
• Weight Converter
• Unit Price Calculator after both packages are in the same unit
• Fuel Economy Comparison
• Paint Coverage Calculator
• Cooking measurement myths
• Baking pan conversion chart when a pan depth has to become cups