Convert Gallons per Minute to Cubic Meters per Second

Formula

m³/s = GPM × 0.0000630901964

or m³/s = GPM ÷ 15850.32314149

Derivation from SI units:

• 1 GPM = 231 in³ ÷ 60 s = 0.003785411784 m³ ÷ 60 s = 6.30901964 × 10⁻⁵ m³/s
• 1 m³/s = 1 m³ ÷ 1 s

Both units are defined exactly, so the factor is exact. Gallon per Minute definition: US gallon per minute; Cubic Meter per Second definition: cubic meter per second.

Worked examples

1. A reading of 3 GPM converts to 0.0001892705892 m³/s.
   3 GPM × 0.0000630901964 = 0.0001892705892 m³/s
2. A value of 25 GPM is 0.00157725491 m³/s.
   25 GPM × 0.0000630901964 = 0.00157725491 m³/s

Where it's used

Gallons per Minute are used for pump, well and irrigation ratings, while cubic meters per second appear in river and channel discharge. Both measure volumetric flow rate (volume per unit time), so the conversion is a fixed factor.

Gallon per Minute to other flow rate units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "gallon [U.S.] per minute (gpm)".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 2, coherent derived units.

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.