Skip to main content

GPM to Lpm Converter

Convert flow rates between gallons per minute and liters per minute. Enter values for instant results with step-by-step formulas.

Reviewed by Manoj Kumar, Mathematics Educator

Reviewed by Manoj Kumar, Mathematics Educator

Formula

LPM = GPM x 3.785411784 | GPM = LPM / 3.785411784

One US gallon equals exactly 3.785411784 liters. To convert gallons per minute to liters per minute, multiply by this factor. To convert liters per minute to gallons per minute, divide by this factor. This applies to US gallons only; Imperial gallons use a factor of 4.54609.

Worked Examples

Example 1: Pool Pump Flow Rate Conversion

Problem:A pool pump is rated at 75 GPM. Convert to LPM and calculate how long it takes to circulate a 15,000-gallon pool.

Solution:Flow rate: 75 GPM x 3.7854 = 283.9 LPM\nPool volume: 15,000 gal x 3.7854 = 56,781 L\nCirculation time: 15,000 / 75 = 200 minutes = 3 hours 20 minutes\nVerification: 283.9 LPM x 200 min = 56,780 L (matches pool volume)

Result:75 GPM = 283.9 LPM | Full pool circulation: 3 hours 20 minutes

Example 2: International Pump Specification

Problem:A European pump specification requires 150 LPM minimum flow. What GPM-rated pump should be purchased from a US supplier?

Solution:GPM = 150 LPM / 3.7854 = 39.63 GPM\nNearest standard pump size: 40 GPM or 50 GPM\nChoose 50 GPM for safety margin (50 x 3.7854 = 189.3 LPM)\n50 GPM provides 26% margin over the 150 LPM requirement

Result:150 LPM = 39.6 GPM minimum | Select 50 GPM pump (189.3 LPM, 26% margin)

Frequently Asked Questions

What are typical flow rates in GPM for residential plumbing?

Residential plumbing fixtures have standard flow rates regulated by federal law in the United States. Low-flow showerheads deliver 2.0 GPM (7.57 LPM) or less, compared to older models at 5+ GPM. Kitchen faucets are limited to 2.2 GPM (8.33 LPM) at 60 psi. Bathroom faucets are limited to 1.5 GPM (5.68 LPM) since 1994. Toilets use 1.6 GPF (gallons per flush) or 1.28 GPF for WaterSense models. A typical garden hose delivers 5 to 10 GPM depending on pressure and hose diameter. A standard residential water heater recovery rate is 30 to 40 GPH (gallons per hour). The total household demand during peak usage (morning showers, laundry, dishwasher) can reach 15 to 30 GPM, which determines the minimum water supply line size.

How do you convert between GPM and other common flow rate units?

Key conversion factors from US GPM include: 1 GPM equals 3.7854 liters per minute, 0.2271 cubic meters per hour, 0.06309 liters per second, 0.1337 cubic feet per minute, 0.002228 cubic feet per second, 1,440 gallons per day, and 0.001440 million gallons per day. For petroleum: 1 GPM equals 34.286 barrels per day. For Imperial: 1 US GPM equals 0.8327 Imperial GPM. To convert from other units to GPM: divide LPM by 3.7854, divide m3/h by 0.2271, multiply CFS by 448.83, or divide barrels per day by 34.286. When performing conversions for engineering calculations, carry at least four significant figures through intermediate steps to maintain accuracy. Use the exact conversion factor (3.785411784) for precision applications in calibration, metering, and custody transfer measurements.

References

Reviewed by Manoj Kumar, Mathematics Educator · Editorial policy