This converter turns imperial gallons into cubic meters instantly, using the exact factor 1 imperial gallon = 0.00454609 cubic meters. Type any number and the result updates as you go — nothing is sent to a server, so the arithmetic happens entirely in your browser.
Exactly 4.54609 litres, about 20% larger than the US gallon. One thousand litres, the SI-derived unit for large volumes like water tanks and gas supply.
Because the relationship is a simple proportion, one multiplication does the whole job. The table further down gives pre-computed values for the amounts people look up most often, and the result panel also reports the reverse conversion so you can check the figure both ways.
The formula
imperial gallons- The amount you are converting, measured in imperial gallons
0.00454609- The exact number of cubic meters in one imperial gallon
cubic meters- The converted result
How it works, step by step
- Enter the number of imperial gallons you want to convert.
- The value is multiplied by 0.00454609, the exact conversion factor.
- The result is displayed in cubic meters, rounded for readability.
- The unrounded value and the reverse conversion appear underneath so you can verify it.
Worked examples
Converting 5 imperial gallons
Multiply 5 by 0.00454609. That gives 0.02273 cubic meters. A quick sanity check: one imperial gallon is smaller than one cubic meter, so the number should get smaller — and it does.
Converting 72 imperial gallons
72 × 0.00454609 = 0.327318 cubic meters. Working backwards, 0.327318 ÷ 0.00454609 returns 72 imperial gallons, which confirms the factor is applied the right way round.
How to read your score
Frequently asked questions
How many cubic meters are in one imperial gallon?
Exactly 0.00454609. Every conversion on this page is that single number multiplied by your input, so the result carries no rounding error beyond what is shown.
What is the formula to convert imperial gallons to cubic meters?
Cubic Meters = imperial gallons × 0.00454609. To reverse it, divide instead: imperial gallons = cubic meters ÷ 0.00454609, which is the same as multiplying by 219.9692483.
Is the imperial gallon bigger than the cubic meter?
No. One imperial gallon is only 0.00454609 of a cubic meter, so the cubic meter is the larger unit.
Why does my answer differ slightly from other imperial-gallons to cubic-meters converters?
Most differences come from rounding the factor too early. This tool keeps full double precision through the calculation and only rounds at the final display step, and it also shows the unrounded value so you can see exactly where any difference appears.
What is a imperial gallon?
Exactly 4.54609 litres, about 20% larger than the US gallon.
What is a cubic meter?
One thousand litres, the SI-derived unit for large volumes like water tanks and gas supply.
Imperial Gallons to cubic meters reference table
| Imperial Gallons | Cubic Meters |
|---|---|
| 0.5 gal | 0.002273 m³ |
| 1 gal | 0.004546 m³ |
| 2 gal | 0.009092 m³ |
| 3 gal | 0.013638 m³ |
| 5 gal | 0.02273 m³ |
| 10 gal | 0.045461 m³ |
| 15 gal | 0.068191 m³ |
| 20 gal | 0.090922 m³ |
| 25 gal | 0.113652 m³ |
| 50 gal | 0.227304 m³ |
| 75 gal | 0.340957 m³ |
| 100 gal | 0.454609 m³ |
| 250 gal | 1.1365 m³ |
| 500 gal | 2.273 m³ |
| 1000 gal | 4.5461 m³ |
Exact factor: 1 imperial gallon = 0.00454609 cubic meters. Values rounded for display.