L/s to CFM Calculator
Convert between liters per second and cubic feet per minute.
About This Calculator
This calculator converts between liters per second (L/s) and cubic feet per minute (CFM), the two most common units for measuring airflow in HVAC systems. L/s is standard in metric countries, while CFM is used in the United States.
I use this conversion constantly when reviewing equipment specs from European manufacturers. Most residential HVAC blowers in the U.S. are rated in CFM, but the moment you’re working with Daikin or Mitsubishi documentation, everything switches to liters per second. Having the right number matters when you’re sizing your ductwork or checking whether a unit delivers adequate airflow.
CFM = L/s × 2.11888
L/s = CFM ÷ 2.11888
A tip from the field: don’t round 2.11888 to 2.12. On residential jobs it barely matters, but on commercial systems I’ve seen those small rounding errors throw off airflow calculations by enough to cause complaints. Always use the full factor when precision counts.
Quick Reference Table
| L/s | CFM |
|---|---|
| 1 | 2.12 |
| 5 | 10.59 |
| 10 | 21.19 |
| 25 | 52.97 |
| 50 | 105.94 |
| 100 | 211.89 |
| 250 | 529.72 |
| 500 | 1059.44 |
In my experience, the values homeowners ask about most fall in the 10–50 L/s range — that covers everything from a bathroom exhaust fan to a small furnace blower. If your number falls outside this table, just plug it into the calculator above.
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