Transparent method
The formula
Worked example
Example inputs
How to interpret the result
A US gallon and an imperial gallon are not the same size, and reaching for the wrong one silently introduces roughly a 20% error into any conversion that crosses between American and British-standard sources, a common enough mix-up that it's worth confirming explicitly rather than assuming. Reference values: a US cup is 236.6 milliliters, a tablespoon is 14.79 and a teaspoon is 4.93, and a US gallon is 3.785 liters or 128 fluid ounces.
A cubic foot holds about 7.48 US gallons and a cubic yard is 27 cubic feet, while an imperial gallon, at 4.546 liters, is about 20 percent larger than a US one.
Before you rely on it
What to check
Confirm whether a source using gallons or quarts means US customary or imperial units before converting, particularly with recipes, fuel figures or product specs sourced internationally.
The common error
Where people go wrong with volume converter calculator
Treating US and imperial gallons as identical. An imperial gallon holds meaningfully more than a US gallon, and using the wrong standard silently shifts every volume figure derived from it.
Sensitivity evidence
How value changes the converted value
| Value | Converted value | 1 unit of "to" in "from" units |
|---|---|---|
| 0.8 | 3 | 0.264 |
| 0.9 | 3.4 | 0.264 |
| 1worked example | 3.8 | 0.264 |
| 1.1 | 4.2 | 0.264 |
| 1.2 | 4.5 | 0.264 |
Every input, tested
Which input moves the converted value most
| Input | Tested from | To | Converted value at each end | Swing |
|---|---|---|---|---|
| From | Milliliters | Cubic meters | 0.001 to 1,000 | 1,000 (100%) |
| To | Milliliters | Cubic meters | 3,785.4 to 0.00379 | 3,785.4 (99974%) |
| Value | 0.9 | 1.1 | 3.4 to 4.2 | 0.757 (20%) |
Step by step
The worked example, input by input
| Input | Value used | What it means |
|---|---|---|
| Value | 1 | |
| From | US gallons | Unit to convert from. |
| To | Liters | Unit to convert to. |
| Converted value | 3.8 | |
| 1 unit of "to" in "from" units | 0.264 | |
Inputs, definitions and assumptions
Value
From
Unit to convert from.
To
Unit to convert to.
Where the inputs come from
Enter the value and choose from milliliters, liters, US gallons, quarts, cups and fluid ounces. This tool uses US customary units, so one gallon is 3.785 liters, and a US cup is about 237 milliliters. Imperial units from the UK, such as the imperial gallon of 4.546 liters, differ and are not included. Read the amount from a measuring cup, a label or a tank spec.
When the result stops applying
Volume of a dry ingredient by cup does not equal its weight, so baking is more accurate by weight. Temperature changes the volume of liquids slightly. Fluid ounces, pints, quarts and gallons differ between US and imperial systems, and dry measures differ again. A cup is 240 milliliters on US nutrition labels but 236.6 in the customary system, so recipes from other countries can be a few percent off.
What to compare it with
Convert weights on the weight converter, cubic measures on the cubic feet and cubic yard calculators, and tank volumes on the aquarium and pool pages. The fuel economy converter handles gallons and liters per distance, and the density calculator relates volume to mass.
People also ask
Frequently asked questions
How many cups are in a gallon?
16 US cups. A US gallon is 4 quarts, each 2 pints, each 2 cups.
How many liters are in a US gallon?
About 3.785 liters. An imperial gallon is larger, about 4.546 liters.
Are fluid ounces and ounces the same?
No. A fluid ounce measures volume and an ounce measures weight, and they are equal only for water-like liquids.