Convert Gallons per Minute to Liters per Second

Formula

L/s = GPM × 0.0630901964

or L/s = GPM ÷ 15.85032314149

Derivation from SI units:

• 1 GPM = 231 in³ ÷ 60 s = 0.003785411784 m³ ÷ 60 s = 6.30901964 × 10⁻⁵ m³/s
• 1 L/s = 10⁻³ m³ ÷ 1 s
• 1 GPM = 0.0000630901964 m³/s ÷ 0.001 m³/s per L/s = 0.0630901964 L/s

Both units are defined exactly, so the factor is exact. Gallon per Minute definition: US gallon per minute; Liter per Second definition: liter per second.

Worked examples

1. A reading of 3 GPM converts to 0.1892705892 L/s.
   3 GPM × 0.0630901964 = 0.1892705892 L/s
2. A value of 25 GPM is 1.57725491 L/s.
   25 GPM × 0.0630901964 = 1.57725491 L/s

Where it's used

Gallons per Minute are used for pump, well and irrigation ratings, while liters per second appear in ventilation rates per person (ASHRAE 62.1, EN 16798). 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 8 (litre).

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