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Cubic Meters to Gallons Converter

Convert cubic meters to gallons — and to liters, quarts, cubic feet, cubic inches, and milliliters — with this free cubic meters to gallons converter. Enter any volume and see it in every unit at once, with both the US gallon and the UK gallon shown separately so there is no confusion.

Common conversions

How it works

Volume is the amount of space something takes up, and the metric and imperial systems measure it in very different ways. A cubic meter is the volume of a cube one meter on each side — a big box, about the size of a washing machine. A liter is a cubic decimeter, exactly one thousandth of a cubic meter, which is why the first conversion on this page is the easiest one in the whole converter: 1 cubic meter is exactly 1,000 liters. A US gallon is defined as 231 cubic inches, which works out to 3.78541 liters, and a UK gallon — the imperial gallon — is defined as 4.54609 liters, about 20 percent larger than the US gallon. That difference is the single most common source of error in volume conversions, and it is why this converter shows both gallons separately.

The conversion factors all come from those definitions. One cubic meter holds 1,000 liters, and each liter is 0.264172 US gallons, so 1,000 × 0.264172 = 264.172 US gallons. For UK gallons the factor is 0.219969 per liter, giving 219.969 UK gallons per cubic meter. A cubic foot is 28.3168 liters, a cubic inch is 0.0163871 liters, a US quart is 0.946353 liters, and a milliliter is one thousandth of a liter. Because every factor is exact, converting through liters — the common base this converter uses — never drifts: go from cubic meters to gallons and back, and you land on the number you started with.

To convert cubic meters to US gallons, multiply by 264.172. To go the other way, divide gallons by 264.172, or multiply by 0.00378541. For liters, multiply cubic meters by 1,000; for cubic feet, multiply by 35.3147. A quick mental shortcut is that 1 cubic meter is about 264 US gallons and about 35 cubic feet, so a 5-cubic-meter tank holds roughly 1,320 US gallons. Use the exact factors when you are ordering a tank, a pool liner, or concrete, where a few percent either way is real money.

These conversions show up everywhere water is measured. Swimming pools are usually quoted in gallons, but pool chemicals are often dosed per cubic meter or per liter. A garden water tank sold as 1 cubic meter holds 1,000 liters, which is 264 US gallons — enough to water a garden for weeks. Concrete is ordered by the cubic yard or cubic meter, while a fish tank is sold by the gallon, so converting between the two is the only way to check that a stand will hold the weight: water weighs about 1 kilogram per liter, so a full cubic meter weighs about a tonne. Whatever the job, the table under the result shows every unit at once, so you can read off the figure your supplier actually uses.

Worked example

A rainwater tank holds 1 cubic meter. How many US gallons is that, and how many liters does a 5-cubic-foot container hold?

Step 1: Write down the first volume — 1 m³.
Step 2: Use the conversion factor — 1 m³ = 264.172 US gallons.
Step 3: Multiply: 1 × 264.172 = 264.172 US gallons.
Step 4: For the second volume, use 1 ft³ = 28.3168 liters.
Step 5: Multiply: 5 × 28.3168 = 141.5842 liters.

Enter 1 in the converter with cubic meters to US gallons selected and it gives exactly the same result: 264.172 US gallons, with 1,000 liters in the table below. Enter 5 cubic feet and the table reads 141.5842 liters — the same answer, in both directions.

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