Cubic Meters to US gallons
1 m³ = 264.172 US gal, derived from exact unit definitions.
| m³ | US gal |
|---|---|
| 1 m³ | 264.2 US gal |
| 2 m³ | 528.3 US gal |
| 5 m³ | 1,320.9 US gal |
| 10 m³ | 2,641.7 US gal |
| 25 m³ | 6,604.3 US gal |
| 50 m³ | 13,208.6 US gal |
| 100 m³ | 26,417.2 US gal |
US gallons = cubic meters × 1000 ÷ 3.785411784
= cubic meters × 264.172052358… (non-terminating)Divide by 3.785411784 after multiplying by 1000. The forward factor 264.172052358… never terminates, so 264.1720524 is a rounding.How to convert cubic meters to US gallons
A cubic metre is the SI coherent unit of volume and is exactly 1,000 litres, so this is the litre conversion with the decimal point moved. It is the conversion you need when an engineering drawing, a European datasheet or a water-utility figure arrives in m³ and has to be quoted to a US client.
- Multiply the cubic-metre figure by 1000 to get litres.
- Divide by 3.785411784.
- Check the magnitude: gallons should be a bit over 264 times the m³ figure.
A 5 m³ water storage tank
- 5 m³ = 5,000 L
- 5000 ÷ 3.785411784 = 1,320.860…
- Round to 1,320.9 US gal
5 m³ = 1,321 US gallons
A 25 m³ bulk tank quoted for a US site
- 25 × 264.172052358 = 6,604.30 US gal
- Nearest standard US size: 6,000 gal or 8,000 gal
25 m³ = 6,604 US gallons
Metric and US-customary tank ranges do not line up. A 25 m³ tank falls between standard US sizes, which usually means either a custom build or a capacity compromise — worth catching at specification stage rather than at delivery.
A 1 m³ IBC, both ways
- 1 m³ = 1,000 L = 264.17 US gal
- Sold in the US as a “275 gallon” tote
- 275 gal = 1.041 m³ — the shell is built oversize
1 m³ = 264.17 US gal
Where the factor comes from
1 m³ = 1000 L (litre ≡ 1 dm³, BIPM)
1 US gal = 3.785411784 L exactly
1 m³ = 1000 / 3.785411784
= 264.172052358148415… non-terminatingNIST SP 811 gives the reverse factor as gallon (U.S.) → m³ = 3.785 412 E-03, un-bolded, because seven digits is a rounding of an exact value.Rounding
264.17 is 0.00002 % low — fine for anything. 264 is 0.065 % low, which is 16 gallons on a 250 m³ tank. 265, occasionally seen, is 0.31 % high and should be avoided; it is no easier to use than 264.
FAQ
How many US gallons are in a cubic meter?
264.172052358… US gallons. A cubic metre is exactly 1,000 litres, and a US gallon is exactly 3.785411784 litres, so the ratio is 1000 ÷ 3.785411784.
How many liters are in a cubic meter?
Exactly 1,000. The litre is defined as one cubic decimetre in the BIPM SI Brochure, and there are 1,000 cubic decimetres in a cubic metre.
Is 264 close enough?
It is 0.065 % low — about 0.17 gallons per cubic metre. Acceptable for an estimate, not for a bulk quantity: on 250 m³ it loses 16 gallons.
Why do European tank specs use m³ and US ones use gallons?
Because each market standardised on its own legal units. Engineering drawings, ISO tank calibration standards and most international suppliers work in cubic metres; US tank trade, delivery tickets and dip charts work in gallons and inches.
Sources and standards
Every factor on this page is traced to the document that defines it. Where a value is exact, it is exact because the cited standard makes it so — not because we rounded it well.
- The International System of Units (SI), 9th edition (SI Brochure)Bureau International des Poids et Mesures (BIPM)https://www.bipm.org/en/si-brochure-9The defining document for the SI, maintained by the treaty organisation that owns the definitions. The litre is exactly one cubic decimetre — 10⁻³ m³ — and is a unit accepted for use with the SI rather than an SI unit itself.
- Handbook 44, Appendix C — General Tables of Units of MeasurementNational Institute of Standards and Technology, U.S. Department of Commercehttps://www.nist.gov/document/2026-nist-handbook-44-appendix-cThe legal-metrology reference for U.S. customary units. Fixes the U.S. liquid gallon at exactly 231 cubic inches and tabulates the full liquid-volume chain (minim → fluid dram → fluid ounce → gill → pint → quart → gallon).
- Special Publication 811, Appendix B.8 — Factors for Units Listed AlphabeticallyNational Institute of Standards and Technologyhttps://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors/nist-guide-si-appendix-b8NIST's master table of conversions into SI. Factors printed in boldface are exact by definition rather than measured or rounded — which is how you tell a defined unit from an approximated one.
- Unit Conversion — Office of Weights and MeasuresNational Institute of Standards and Technologyhttps://www.nist.gov/pml/owm/metric-si/unit-conversionNIST's index page explaining which of its publications governs which kind of conversion: SP 811 for exact factors, Handbook 44 Appendix C for trade and commerce, Handbook 133 Appendix E for packaged goods.
Every linked source above was retrieved and checked on 2026-09-02. Factors quoted as exact are exact by definition in the cited document, not rounded by us.