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Convert cubic feet per minute (CFM) to liters per second (L/s) instantly. Our free flow rate converter handles bidirectional CFM-to-L/s conversion with a detailed formula reference, real-world context tables, and step-by-step examples for HVAC, compressed air, and ventilation work.
Conversion Formula
L/s = CFM × 0.471947
CFM = L/s ÷ 0.471947
The table below lists 18 commonly referenced CFM values with their liters-per-second equivalents and a real-world context so you can quickly gauge the scale of each flow rate.
| CFM | Liters per Second (L/s) | Typical Application |
|---|---|---|
| 1 | 0.47 | Very small fan or vent |
| 5 | 2.36 | Small electronics cooling fan |
| 10 | 4.72 | Small spot ventilator |
| 25 | 11.80 | Desk fan or range hood low setting |
| 50 | 23.60 | Minimum bathroom exhaust fan |
| 75 | 35.40 | Standard bathroom exhaust fan |
| 100 | 47.19 | Large bathroom or small kitchen hood |
| 150 | 70.79 | Kitchen range hood (medium) |
| 200 | 94.39 | Kitchen range hood (high) |
| 300 | 141.58 | Attic ventilation fan |
| 400 | 188.78 | Whole-house fan (small home) |
| 500 | 235.97 | Workshop dust collector |
| 750 | 353.96 | Large commercial exhaust system |
| 1000 | 471.95 | Small industrial air handler |
| 1500 | 707.92 | Commercial HVAC air handler |
| 2000 | 943.89 | Large commercial rooftop unit |
| 3000 | 1415.84 | Industrial ventilation system |
| 5000 | 2359.74 | Large industrial air handling unit |
Cubic feet per minute (CFM) is an imperial unit of volumetric flow rate that describes how many cubic feet of air or gas pass a given point each minute. It is the dominant airflow specification in the United States and is used extensively in HVAC equipment ratings, air compressor specifications, exhaust fan sizing, and pneumatic tool requirements. A standard household bathroom exhaust fan, for example, typically moves between 50 and 110 CFM, while a large commercial air handling unit may deliver 5,000 CFM or more. Because CFM measures volume rather than mass, the actual amount of air (by weight) at a given CFM reading depends on temperature, humidity, and atmospheric pressure.
Liters per second (L/s) is the metric counterpart for measuring volumetric flow. It is widely adopted in international building codes, ISO ventilation standards, and engineering specifications outside North America. One liter per second represents one thousandth of a cubic meter flowing past a point each second. The unit provides a convenient human-scale number for most building ventilation scenarios: a typical office requires roughly 10 L/s of fresh air per person, while a residential kitchen range hood might need 50 to 100 L/s. Converting between CFM and L/s is essential when working with equipment manufactured in different regions or when following international design standards.
L/s = CFM × 0.471947
Derived from: 1 ft³ = 28.3168 L, and 1 min = 60 s, so 28.3168 ÷ 60 = 0.471947
To reverse the conversion (L/s to CFM), divide by the same factor: CFM = L/s ÷ 0.471947, or equivalently multiply by 2.11888.
Question: Convert 50 CFM to liters per second.
This is the minimum ventilation for a standard bathroom under most building codes.
Question: A range hood is rated at 400 CFM. What is that in L/s?
High-power kitchen hoods for commercial stoves are often rated this high.
Question: A home-shop compressor delivers 12 CFM. Convert to L/s.
Enough for most hobby-grade spray guns and air nailers running one at a time.
Quick estimate: Divide the CFM value by 2, then subtract about 5 percent. For example, 100 CFM ÷ 2 = 50, minus 5% = 47.5 L/s (actual: 47.19 L/s). This gives a fast ballpark within about 1 percent accuracy for most practical values.
Common ventilation rates for residential and light commercial spaces.
| Space Type | CFM | L/s |
|---|---|---|
| Small bathroom (50 sq ft) | 50 | 23.6 |
| Large bathroom (100 sq ft) | 100 | 47.2 |
| Residential kitchen | 200 | 94.4 |
| Open-plan office (per person) | 20 | 9.4 |
| Conference room (10 people) | 150 | 70.8 |
| Server room (per rack) | 300 | 141.6 |
Typical CFM demands for common pneumatic tools.
| Pneumatic Tool | CFM Required | L/s Required |
|---|---|---|
| Brad nailer | 1 | 0.47 |
| Finish nailer | 2.5 | 1.18 |
| Blow gun | 3 | 1.42 |
| HVLP spray gun | 8 | 3.78 |
| Impact wrench (3/8") | 5 | 2.36 |
| Impact wrench (1/2") | 7 | 3.30 |
| Die grinder | 5 | 2.36 |
| Sandblaster | 20 | 9.44 |
Reverse lookup for common metric flow rates.
| L/s | CFM | Context |
|---|---|---|
| 5 | 10.6 | Small exhaust or fume hood |
| 10 | 21.2 | Per-person office fresh air |
| 25 | 53.0 | Standard bathroom exhaust |
| 50 | 105.9 | Medium residential kitchen |
| 100 | 211.9 | Large kitchen range hood |
| 250 | 529.7 | Commercial AHU supply |
| 500 | 1059.4 | Large commercial system |
International HVAC standards (ISO 16890, EN 13779) specify ventilation rates in L/s, while US equipment uses CFM. Accurate conversion prevents oversizing or undersizing ductwork and air handlers.
Compressor manufacturers and pneumatic tool specs may use either unit. Converting correctly ensures adequate compressed air delivery and prevents tool starvation or wasted energy.
Fresh air ventilation rates per occupant are often specified in L/s in ASHRAE 62.1 and international codes. Getting the conversion right directly affects occupant health and comfort.
When sourcing fans, blowers, or air handling units from global suppliers, accurate unit conversion ensures you receive equipment that meets your design airflow requirements.
CFM uses cubic feet and minutes, while L/s uses liters and seconds. You must account for both the volume conversion (1 ft³ = 28.3168 L) and the time conversion (1 min = 60 s). Simply converting cubic feet to liters without adjusting minutes to seconds gives a result that is 60 times too large.
SCFM (Standard CFM) and ACFM (Actual CFM) are different. SCFM is normalized to standard temperature and pressure. If your datasheet says SCFM, the volumetric conversion factor is the same, but the mass flow may differ from actual conditions.
The precise conversion factor is 0.471947443... (often rounded to 0.4719 or 0.472). For engineering calculations where every decimal matters, use at least four decimal places. For quick estimates, dividing by 2 and subtracting 5 percent is close enough.
Some specifications use liters per minute (L/min) rather than liters per second (L/s). If you need L/min instead, multiply CFM by 28.3168 (not 0.471947). Mixing up L/min and L/s results in a 60-fold error.
After converting CFM to L/s, divide the result by 0.471947. If you get back to the original CFM value (within rounding), your conversion is correct. This simple check catches arithmetic mistakes.
1 cubic foot per minute (CFM) equals approximately 0.471947 liters per second (L/s). This factor comes from dividing 28.3168 liters (1 cubic foot) by 60 seconds (1 minute).
Most building codes require at least 50 CFM (23.6 L/s) for standard bathrooms. The general rule is 1 CFM per square foot of bathroom area, so a 100 sq ft bathroom needs at least 100 CFM (47.2 L/s).
Use an anemometer to measure air velocity at a duct opening, then multiply velocity (in feet per minute) by the cross-sectional area of the duct (in square feet) to get CFM. Professional HVAC technicians use calibrated flow hoods for more accurate measurements.
Yes. CFM measures volumetric flow, not mass flow. At higher altitudes air is less dense, so the same CFM contains less air mass. Some applications specify SCFM (Standard CFM) to normalize readings to sea-level conditions.
CFM is the actual volumetric flow at current temperature and pressure, while SCFM (Standard Cubic Feet per Minute) is normalized to standard conditions (typically 68 degrees F and 14.7 psi). SCFM allows fair comparison of flow rates measured at different altitudes or temperatures.
Add up the CFM requirements of all pneumatic tools you will run simultaneously, then add a 30 percent safety margin. Most home workshops need 4 to 6 CFM (1.9 to 2.8 L/s), while professional shops may need 15 to 30 CFM (7 to 14 L/s).
HVAC equipment manufactured in the United States is typically rated in CFM, while international standards such as ISO 16890 and many building codes outside the US use liters per second. Engineers must convert between the two when designing or specifying systems for global projects.
Yes. Multiply CFM by 1.699 to get cubic meters per hour. Alternatively, convert CFM to L/s first (multiply by 0.471947), then multiply by 3.6 to obtain m3/h.
This calculator is provided for informational and educational purposes only. While we strive for accuracy, results should be verified for critical engineering applications. Always consult qualified professionals for HVAC system design and industrial specifications.