GPM to LPM Converter

GPM vs LPM: Understanding Flow Rate Units

Gallons per minute (GPM) and litres per minute (LPM) are the two most common volumetric flow rate units in the world. GPM is standard in the USA and some other countries; LPM (and its SI equivalent, L/s) is used everywhere else.

Conversion Factors

1 GPM (US) = 3.78541 LPM 1 LPM = 0.264172 GPM

Other useful conversions:

• 1 GPM = 0.0631 L/s
• 1 GPM = 0.00228 m³/min
• 1 m³/hr = 4.403 GPM
• 1 CFS (cubic feet per second) = 448.83 GPM

How to Use This Calculator

Enter a value in GPM or LPM — the calculator converts instantly between both, plus shows m³/hr, L/s, and CFS equivalents.

Practical Examples

Example 1: Residential water meter reads 10 GPM during a shower. That's 10 × 3.785 = 37.85 LPM — typical for a shower (8–12 LPM is standard efficient flow).

Example 2: Pump datasheet shows 500 LPM capacity. That's 500 / 3.785 = 132 GPM — suitable for a large irrigation zone.

Example 3: Cooling tower requires 1,000 GPM. In metric: 1,000 × 3.785 = 3,785 LPM = 227.1 m³/hr.

Common Applications Requiring Unit Conversion

• Pump datasheets (often in GPM) vs. pipe sizing software (metric)
• Importing US irrigation equipment to metric countries
• HVAC cooling water system design (mixing US and European specifications)
• Fire suppression system design to international standards