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Flow Rate Converter — GPM, CFM, L/min and m³/h
Convert 11 volumetric flow units. Distinguish US and Imperial GPM, convert CFM to L/min or m³/h, check reference tables, copy results and export CSV. No registration required.
About Flow Rate Converter — GPM, CFM, L/min and m³/h
GPM and CFM to L/min: compare specifications in the same units
Select a common conversion for US or Imperial GPM, CFM or L/min, then enter a flow rate. Compare pump specifications in GPM and L/min, or ventilation rates in CFM and m³/h. Matching units alone does not make specifications comparable when fluid, temperature, pressure or other conditions differ.
Copy the selected formula and result, or copy just the number without thousands separators. Export all 11 results as CSV with the input, explicit US/Imperial unit names and out-of-range status. The reference tables show fixed values, independent of your input.
Convert between 11 volumetric flow units
Supported units are m³/s, m³/min, m³/h, L/s, L/min (LPM), L/h, mL/s (cc/s), GPM(US), GPM(UK), CFM and CFS. Choose the input and output units to see the selected result and all 11 conversions. Changing or swapping units keeps your number and interprets it in the new input unit.
Use ASCII digits, with up to 100 characters. Negative numbers, zero, decimals and scientific notation are supported; thousands separators, full-width digits and appended unit names are not. Empty inputs have no result; invalid inputs can be corrected. Results are approximate, with up to 12 significant digits. Individual results outside the numeric representation range are marked “Out of range”. Displayed digits do not guarantee measurement accuracy. Negative values represent signed flow; use nonnegative values for magnitude.
US gallons, Imperial gallons and cubic feet
1 L = 0.001 m³, 1 US liquid gallon = 3.785411784 L, 1 Imperial gallon = 4.54609 L and 1 international foot = 0.3048 m. Therefore, 1 GPM(US) = 3.785411784 L/min, 1 GPM(UK) = 4.54609 L/min, 1 CFM = 28.316846592 L/min and 1 CFS = 0.028316846592 m³/s.
1 m³/h = 1000/60 L/min ≈ 16.6667 L/min; 1 m³/s = 3600 m³/h = 60000 L/min. For example, 100 CFM = 169.901079552 m³/h, or approximately 170 m³/h. For the same nonzero flow, the absolute numeric value in CFM is smaller than in L/min. Zero remains zero in both units.
Gas-state corrections and mass flow require separate calculations
This tool changes unit scales only. It does not correct for temperature, pressure, humidity or compressibility between actual and reference conditions, such as CFM versus SCFM or m³/h versus Nm³/h. Align the reference conditions when comparing gas flow specifications.
Mass flow [kg/s] = volumetric flow [m³/s] × density [kg/m³]. Density depends on the fluid and its conditions. This tool has no density input and does not convert volume flow into mass flow. The mass flow unit converter (Japanese) also only converts between units of mass flow. Neither tool determines required equipment flow rates or operating conditions.
Frequently asked questions
- Q. How do I convert L/min to m³/h?
- Multiply L/min by 0.06. For example, 1 L/min = 0.06 m³/h and 100 L/min = 6 m³/h. To convert m³/h to L/min, multiply by 1000/60. LPM means litres per minute, the same as L/min.
- Q. How do I convert CFM to m³/h?
- Multiply CFM by 1.69901079552. Thus 1 CFM = 1.69901079552 m³/h and 100 CFM = 169.901079552 m³/h. CFM means cubic feet per minute (ft³/min); this tool uses the international foot. Gas temperature and pressure corrections are not included.
- Q. How many L/min is 1 GPM?
- It depends on the gallon standard. 1 US liquid GPM = 3.785411784 L/min; 1 Imperial GPM = 4.54609 L/min. An Imperial gallon is about 20.095% larger than a US liquid gallon. Check whether the specification states US, UK or Imperial.
- Q. Does converting to CFM make the number larger?
- For the same nonzero flow, the absolute value in CFM is smaller than in L/min. For example, -100 L/min is about -3.53147 CFM. Zero stays zero. Since 1 CFM = 28.316846592 L/min, divide L/min by 28.316846592 to get CFM. For example, 100 CFM is about 2831.68 L/min.
- Q. Can I convert CFM to SCFM or m³/h to Nm³/h?
- No gas-state correction is performed here. Converting between actual and reference-condition volumetric flow requires the chosen reference conditions and actual temperature, pressure and other relevant inputs. Do not treat a unit-only conversion as a state-corrected result.
Sources and specifications
- NIST: NIST Guide to the SI, Appendix B.8: Factors for Units Listed Alphabetically(Flow and volume conversion factors)
- NIST: Gas Flow Standards(Gas density and state conditions)
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