Flow Rate Conversion
Quick answer: 1 m³/h = 1,000 L/h ≈ 16.67 L/min ≈ 0.2778 L/s, 1 L/s = 3.6 m³/h, 1 US GPM ≈ 3.785 L/min ≈ 0.227 m³/h and 1 CFM ≈ 1.699 m³/h.
m³/h, L/s, L/min, m³/s, US and UK gallons per minute (GPM), CFM and barrels per day – for water, heating, ventilation and pumps.
How the calculation works
Enter a flow rate and choose the starting unit (for example m³/h, L/min or GPM). The table shows the same flow in cubic metres and litres per second, minute, hour and day, US and UK gallons, cubic feet (CFM), bushels, acre-feet and barrels per day.
Formula and assumptions
The base unit is m³/s. Flow is volume over time, so the volume factor is divided by the time factor: 1 L/min = 0.001 m³ / 60 s, 1 m³/h = 1 m³ / 3,600 s. 1 US gal = 3.785411784 L, 1 UK gal = 4.54609 L, 1 ft³ = 28.316846592 L. A year is 365.25 days.
More worked examples
- Underfloor heating at 2.4 L/min per loop: 2.4 × 60 = 144 L/h = 0.144 m³/h.
- A pump at 5 m³/h: 5 ÷ 3.6 ≈ 1.39 L/s.
- A 200 CFM fan: 200 × 1.699 ≈ 340 m³/h.
- A 10 GPM (US) tap: 10 × 3.785 ≈ 37.9 L/min.
Units of flow rate
| Unit | in L/min | in m³/h |
|---|---|---|
| 1 L/s | 60 | 3.6 |
| 1 L/min | 1 | 0.06 |
| 1 m³/h | 16.667 | 1 |
| 1 US gal/min | 3.7854 | 0.2271 |
| 1 UK gal/min | 4.5461 | 0.2728 |
| 1 CFM (ft³/min) | 28.317 | 1.699 |
Common mistakes
- Dividing by 60 instead of 3,600 when converting m³/h to L/s.
- Confusing US and UK gallons (20 % difference).
- Mixing volumetric (m³/h) and mass flow (kg/h) without the density.
Frequently asked questions
How many L/min is 1 m³/h?
1 m³/h = 1,000 L / 60 min ≈ 16.67 L/min.
How do I convert L/s to m³/h?
Multiply by 3.6: 2 L/s = 7.2 m³/h.
How many m³/h is 1 CFM?
1 CFM (cubic foot per minute) ≈ 1.699 m³/h and 1 m³/h ≈ 0.589 CFM.
How many litres per minute is 1 GPM?
1 US GPM ≈ 3.785 L/min and 1 UK (imperial) GPM ≈ 4.546 L/min.
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Publisher: Art-Visum d.o.o. · Content reviewed:
Calculations use common consumption rates and manufacturers' technical data sheets; results are estimates. Methodology · Standards · About