Convert Gallons per Minute to SLPM

Formula

SLPM = GPM × 3.785411784

Derivation from SI units:

• 1 GPM = 231 in³ ÷ 60 s = 0.003785411784 m³ ÷ 60 s = 6.30901964 × 10⁻⁵ m³/s
• 1 SLPM = 10⁻³ m³ ÷ 60 s, measured at standard reference conditions
• 1 GPM = 0.0000630901964 m³/s ÷ 0.00001666666666667 m³/s per SLPM = 3.785411784 SLPM
• Standard ↔ actual: Q_actual = Q_standard × (T_actual / T_ref) × (P_ref / P_actual), absolute T and P.

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

Worked examples

1. A reading of 3 GPM converts to 11.35623535 SLPM.
   3 GPM × 3.785411784 = 11.35623535 SLPM
2. A value of 25 GPM is 94.6352946 SLPM.
   25 GPM × 3.785411784 = 94.6352946 SLPM

Where it's used

Gallons per Minute are used for pump, well and irrigation ratings, while SLPM appear in mass flow meters and controllers. 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)".
• SEMI E12 Guide for Standard Temperature and Pressure Used in the Measurement of Mass Flow, SEMI , standard conditions 0 °C, 101.325 kPa.
• ISO 6358-1:2013 Pneumatic fluid power — Determination of flow-rate characteristics of components using compressible fluids, International Organization for Standardization .

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