cubic meters to gallons

A pool builder working from a metric plan — 50 m³, say — and an American pool-supply catalog that sells chlorine by the gallon will meet at 264.172052358, the exact number of US gallons in a cubic meter. The number is a reciprocal of the gallon's 231 in³ definition and the 1959 inch, so it carries no approximation; it just looks alarming because it is built from an ancient English volume standard against the modern metric cube.

1 cubic meter = 264.172 gallons, and 1 gallon = 0.003785411784 cubic meters. Every value on this page scales by the same factor: multiply cu m by 264.172. Worked: 10 cu m = 2,641.72 gallons; 100 cu m = 26,417.2 gallons.

By EnginStack Editorial Team | Reviewed against NIST, BIPM and primary-source documentation About →
cubic meters
13,208.60261791 gallons
50 cubic meters = 13,208.60261791 gallons 50 gallons = 0.18927059 cubic meters

Authority: NIST SP 811 (SI usage guide) and the 1959 International Yard and Pound Agreement. The coefficient above is a defined value — it does not come from measurement and carries no uncertainty.

cubic meters to gallons

One cubic meter is exactly 264.172052358 US gallons — the factor is exact because both units are legally defined, and it is the reciprocal of 0.003785411784. The engineering situations where this matters are almost always chemical-dosing: pool chlorination, water-treatment alum feed, cooling-tower biocide, all spec the treatment in gallons while the tank volume is in cubic meters. Get the dose per m³ wrong by forgetting the 264, and the treatment is off by a factor of more than two hundred.

gallons = cubic meters × 264.172052358
1 cubic meter = 264.172052358 US gallons — the reciprocal of the 231 in³ gallon
The factor is exact: 1 / 0.003785411784.

Worked Examples

Example 1: Convert a 50 m³ backyard swimming pool

50 × 264.172052358 = 13,208.6 gal

Example 2: Convert a one cubic meter reference volume

1 × 264.172052358 = 264.172 gal

Example 3: Convert a 1,000 m³ reservoir segment

1,000 × 264.172052358 = 264,172 gal

Common cubic meters to gallons Conversions

cubic metersgallonsContext
1 m³264.2 galOne cubic meter — the metric anchor.
50 m³13,209 galA backyard swimming pool.
100 m³26,417 galA large commercial pool.
1,000 m³264,172 galA municipal reservoir segment.
10,000 m³2,641,720 galA fire-protection water tank.

Engineering Context

The gallons to cubic meters page inverts this constant. It sits in the volume family next to liters to cubic meters and gallons to liters — the latter being the everyday version of the same transatlantic bridge. Water-treatment dosing ties this page to the density and weight families.

Which gallon is the one thing that matters on this page. A cubic meter is 264.172 US gallons but only 219.969 imperial gallons, a difference of about twenty percent, and the two are distinguished in the source documents only by context. Pool chemicals, US municipal metering and American fuel volumes use the 231 cubic inch gallon; older British engineering, fuel economy in the United Kingdom and Caribbean water tariffs may use the imperial gallon defined from 4.54609 liters. If a converted volume looks about a fifth low, the wrong gallon was used before any arithmetic was done.

More: gal to m³ · L to m³ · gal to L · Volume & Cooking Guide · Volume Hub

Related Unit Converters

gallons to cubic meters liters to cubic meters Gallons to Liters Volume & Cooking Conversion Guide Volume Converters

Frequently Asked Questions

How many gallons are in a cubic meter?

Exactly 264.172052358 US gallons. It is the reciprocal of the US gallon's volume in cubic meters: 1 gal = 231 in³ = 0.003785411784 m³, so 1 m³ = 1 / 0.003785411784 = 264.172052358 gal.

Why does pool chemistry use gallons when pool volume is metric?

Because dosing products are sold in the US market with instructions in gallons, while pool designs from metric countries quote volume in cubic meters. The mismatch is exactly why this converter exists — dose per m³ and dose per gallon are 264 apart.

How accurate is '1 m³ = 264 gallons'?

It is within 0.07% — fine for estimates. For chemical dosing, use the full factor 264.172052358, since a 0.07% error in a treatment rate can compound over large water volumes.