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Litres per Minute to GPM Calculator

Convert metric flow rates into US gallons per minute for American pump and fixture data.

Computed in your browser — nothing you enter is uploaded. Figures are presented for United States against IRC 2024, and every formula is cited under regulatory standards below.

Last verified 2026-08-26 · v1.0.0

Market
Imperial · sales tax

Flow rate

10.04 GPM

High confidence

1 L = 1/3.785411784 US gallons. Litres per second is a common alternative in European data — multiply by 60 before converting.

Conversion factor applied
0.26 GPM per L/min

American pump curves and fixture tables are published in gallons per minute, so metric design figures have to be brought across before equipment can be selected. The arithmetic is straightforward; the reliable source of confusion is which metric unit the original figure uses. European drainage and commercial water design frequently work in litres per second rather than per minute, and a result that comes out sixty times too small is almost always that step being skipped. For gas and compressed air the volume conversion still holds, but the figures are quoted at reference temperature and pressure, so two flow rates in identical units may not describe comparable conditions unless those references match.

Add the equipment this sizes

This result is a specification — 10.039 GPM — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.

Preliminary estimate, not certified engineering. This tool produces an indicative quantity calculation for planning purposes only — it is not a certified structural analysis, a guaranteed material takeoff, or a substitute for building department approval. Always verify measurements on-site and have a licensed contractor or structural engineer review any load-bearing, code-sensitive, or safety-critical work before purchasing materials or starting construction. Spotted an arithmetic or standards error? Report it to contact@craftquantities.com with your inputs — confirmed fixes become pinned regression tests.

[Schema Verified] Computed in alignment with American Concrete Institute (ACI 318-19) formulas and International Residential Code (IRC 2024) spatial boundaries.

Regulatory standards & verification citations

  • 1 US gallon = 3.785411784 L, so 1 L/min = 0.264172 GPM

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Frequently asked questions

My data is in litres per second. What do I do?
Multiply by sixty to get litres per minute first, then convert. Litres per second is common in European drainage and commercial water design, and a result sixty times smaller than expected almost always means this step was missed.
Is this the same for gas or air?
The volume conversion is, but gas flow is usually quoted at a stated temperature and pressure, so two figures in the same units may not be comparable. Check the reference conditions before treating them as equivalent.
What is a typical shower flow?
Modern water-efficient showers run around 6 to 9 litres per minute, which is roughly 1.6 to 2.4 GPM. US regulations have capped showerhead flow for decades, so American fixtures cluster near the lower end of that range.