Volume Conversion
Free Volume conversion Converter for volume & weight units. Enter a value to see equivalent measurements across systems.
Volume Conversion
Calculator
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Formula: Target = Value x (Source mL factor / Target mL factor)
Worked example — 15,000 gal = 56,781.15 L = 2,005.19 ft3
Formula
Target = Value x (Source mL factor / Target mL factor)
All volume conversions pass through milliliters as the base unit. Each unit has a fixed conversion factor to milliliters. To convert between any two units, multiply the input by its mL factor, then divide by the target mL factor. Key factors: 1 L = 1000 mL, 1 US gal = 3785.41 mL, 1 cup = 236.588 mL, 1 fl oz = 29.5735 mL.
Worked Examples
Example 1: Pool Volume
Problem:A pool holds 15,000 gallons of water. How many liters and cubic feet is that?
Solution:Liters: 15,000 x 3.78541 = 56,781.15 L Cubic feet: 15,000 / 7.48052 = 2,005.19 ft3 Cubic meters: 56,781.15 / 1000 = 56.78 m3
Result:15,000 gal = 56,781.15 L = 2,005.19 ft3
Example 2: Recipe Scaling
Problem:Convert 750 mL of broth to cups and fluid ounces.
Solution:Cups: 750 / 236.588 = 3.17 cups Fluid ounces: 750 / 29.5735 = 25.36 fl oz Pints: 750 / 473.176 = 1.585 pt
Result:750 mL = 3.17 cups = 25.36 fl oz
Frequently Asked Questions
How do I convert gallons to liters?
To convert US gallons to liters, multiply by 3.78541. For example, 5 US gallons equals 18.927 liters (5 x 3.78541). Note that an Imperial gallon is larger at 4.54609 liters. This difference is important when following recipes or instructions from different countries. For a quick mental estimate, multiply gallons by 3.8 to get a close approximation in liters.
What is the difference between US and Imperial fluid measurements?
US and Imperial fluid measurements differ in size despite sharing some names. A US gallon is 3,785.41 mL while an Imperial gallon is 4,546.09 mL, making the Imperial gallon about 20% larger. Similarly, a US fluid ounce is 29.5735 mL while an Imperial fluid ounce is 28.4131 mL. This means US and Imperial cups, pints, and quarts also differ. Always check which system a recipe or specification uses to avoid measurement errors.
How many cups are in a gallon?
There are 16 US cups in a US gallon. Breaking it down further: 1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces. For Imperial measurements, there are approximately 18.18 Imperial cups in an Imperial gallon. Knowing these relationships helps when scaling recipes up or down, and this converter handles all the math automatically for any volume unit combination.
How do I convert cubic feet to gallons?
One cubic foot equals approximately 7.48052 US gallons. To convert, multiply cubic feet by 7.48052. For example, a 10 cubic foot container holds about 74.8 gallons. This conversion is commonly needed for aquariums, water tanks, pools, and HVAC systems. One cubic foot also equals 28.3168 liters or 28,316.8 milliliters. For Imperial gallons, one cubic foot equals approximately 6.22884 Imperial gallons.
What is the difference between a fluid ounce and an ounce of weight?
A fluid ounce measures volume while an avoirdupois ounce measures mass, and the two only coincide numerically for water, because one US fluid ounce holds about 29.57 mL and water is close to one gram per millilitre. For oil, honey or flour they diverge sharply, so a recipe calling for 8 ounces of a dry ingredient almost never means one cup. Establish whether the source is a volume or a scale measurement before converting.
How do litres relate to cubic metres and cubic centimetres?
One litre is defined as exactly one cubic decimetre, which makes one millilitre exactly one cubic centimetre and one cubic metre exactly 1000 litres. That is why engine displacement is quoted interchangeably in cc and litres, and why a tank measured in metres converts to litres by multiplying the cubic-metre volume by 1000. The relationship is exact, with no rounded factor involved.
Why do US dry pints differ from liquid pints?
The United States kept two separate capacity systems. The liquid pint is 473.176 mL and descends from the wine gallon, while the dry pint used for berries and produce is about 550.6 mL and descends from the larger bushel-based measure. That is a difference of roughly 16 percent, so a dry quart of fruit holds noticeably more than a liquid quart. Confirm which series a label uses before converting.
How many tablespoons and teaspoons are in a US cup?
A US customary cup of 236.588 mL contains 16 tablespoons or 48 teaspoons, so one tablespoon is 14.787 mL and one teaspoon is 4.929 mL, with three teaspoons to a tablespoon. The Australian tablespoon, by contrast, is defined as 20 mL and holds four teaspoons, which is a frequent source of error when following recipes written in another region.
How do I convert a tank size into gallons?
Compute the internal volume in cubic inches, then divide by 231, since one US gallon is defined as exactly 231 cubic inches. A rectangular tank 24 by 12 by 12 inches holds 3456 cubic inches, which is 14.96 gallons. For a cylinder use pi times the radius squared times the height. Always work from internal dimensions, because wall thickness can remove several percent of the nominal capacity.
When should I measure by weight instead of volume?
Whenever the ingredient can be compressed or settles, which makes its effective density inconsistent. Scooped flour varies substantially between fills of the same cup, while water, milk and sugar are far more repeatable by volume. Weighing removes the packing variable entirely, which is why baking references increasingly give grams. Volume measures remain fine for liquids and for anything where a few percent will not change the outcome.
References
Background & Theory
1 US gallon = 3.785411784 L, 1 imperial gallon = 4.54609 L, and 1 litre = 1,000 cm3 - all exact by definition. The US and imperial systems share unit names but not sizes, and the imperial gallon is about 20 percent larger.
Conversion reference table
| Conversion | Equivalent | Exact or rounded? |
|---|---|---|
| 1 litre | 1,000 cubic centimetres = 0.001 cubic metres | Exact by definition |
| 1 US liquid gallon | 3.785411784 litres (231 cubic inches) | Exact |
| 1 imperial gallon | 4.54609 litres | Exact |
| 1 US fluid ounce | 29.5735295625 millilitres | Exact |
| 1 imperial fluid ounce | 28.4130625 millilitres | Exact |
| 1 cubic foot | 28.316846592 litres = 7.48051948 US gallons | Exact / derived |
| 1 cubic inch | 16.387064 cubic centimetres | Exact |
| 1 US cup (customary) | 236.5882365 millilitres | Exact |
The fluid ounces run opposite to the gallons: the imperial gallon is larger but the imperial fluid ounce is smaller, because an imperial gallon divides into 160 ounces while a US gallon divides into 128. That is why a UK pint of 20 imperial ounces is 568 mL while a US pint of 16 US ounces is only 473 mL. Dry measures are a third system again - the US dry pint and dry quart are about 16 percent larger than their liquid namesakes.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator · Editorial policy
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