By Zencalcy Editorial TeamLast reviewed About us
Metric plumbing and irrigation equipment is rated in litres per minute, while US pumps and fixtures use gallons per minute. The conversion is 3.785 litres per US gallon, but the useful figure is usually per hour or per day — especially for irrigation scheduling and tank refill times.
Convert any flow rate to litres per minute.
L/min = litres ÷ minutes L/min = gpm × 3.7854
One cubic metre is 1,000 litres, so m³/h = L/min × 0.06. US gallons per minute convert with 3.7854; imperial gallons use 4.546. Most European fixtures are rated at 3 bar dynamic pressure, so real flow is lower on a gravity system.
| Symbol | Meaning |
|---|---|
| V | Volume in litres. |
| t | Time in minutes. |
| Q | Flow in litres per minute. |
20 ÷ 2.5 = 8 L/min, which is 2.11 gpm and 0.48 m³/h.
Continue with the Pool Calculator, Round Pool Volume Calculator, Pond Calculator, or the Tank Volume Calculator — or browse more tanks, pools & flow and all construction calculators.
Divide by 3.7854. So 10 L/min is 2.64 gpm, and 20 L/min is 5.28 gpm.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026