Formula
NIST defines a US liquid gallon as exactly 231 cubic inches. At exactly 2.54 cm per inch, that is 231 × 2.54³ = 3,785.411784 cm³, or 3.785411784 liters. Because both rates are measured per minute, only the volume unit changes:
US gal/min = L/min ÷ 3.785411784
For the reverse conversion, multiply US gal/min by 3.785411784. Always check whether a source means US or imperial gallons before using a value labeled only “gpm.”
Worked example: a 60 L/min pump
- Start with the pump’s stated volumetric flow: 60 L/min.
- Divide by 3.785411784 L per US gallon: 60 ÷ 3.785411784 = 15.850323….
- Round for display: 60 L/min ≈ 15.8503 US gal/min.
As a check, 15.850323… × 3.785411784 returns 60 L/min. The rounded figure is suitable for a quick specification comparison; use the precision required by your application.
Check it in the converter
- Open the Flow Rate Converter.
- Choose the L/min → US gpm quick pair and enter 60.
- Read the result in US gal/min. Use the swap control if you need the reverse direction.
US gpm and imperial gal/min differ
One imperial gallon is exactly 4.54609 L. The same 60 L/min is about 13.1982 imperial gal/min, rather than 15.8503 US gal/min. Selecting the wrong gallon definition changes the result by roughly 20%. The converter names the two units separately.
This calculation converts volumetric flow. Converting to mass flow, such as kg/s, also requires the fluid’s density. A flow velocity in m/s additionally depends on the cross-sectional area; neither follows from L/min alone.