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Convert flow rates between cubic feet per minute (CFM) and liters per second (L/s) instantly with our free online calculator.
L/s = CFM × 0.471947
CFM = L/s ÷ 0.471947
| CFM | Liters per Second (L/s) |
|---|---|
| 1 | 0.4719 |
| 5 | 2.3597 |
| 10 | 4.7195 |
| 25 | 11.7987 |
| 50 | 23.5973 |
| 75 | 35.3960 |
| 100 | 47.1947 |
| 150 | 70.7921 |
| 200 | 94.3894 |
| 300 | 141.5841 |
| 500 | 235.9735 |
| 750 | 353.9603 |
| 1000 | 471.9470 |
Cubic feet per minute (CFM) is an imperial unit measuring volumetric flow rate, commonly used in the United States for air conditioning, ventilation, and compressed air systems. CFM indicates how many cubic feet of air or gas pass through a given point in one minute. It's the standard specification for HVAC equipment, air compressors, fans, and pneumatic tools. For example, a typical bathroom exhaust fan moves 50-80 CFM, while industrial air compressors can deliver 100-500 CFM or more. CFM ratings help engineers properly size ventilation systems and ensure adequate airflow for comfort and safety.
Liters per second (L/s) is the metric unit for volumetric flow rate in the International System of Units. It measures the volume of fluid in liters flowing past a point each second. L/s is widely used internationally for both liquid and gas flow measurements in HVAC design, plumbing specifications, and scientific applications. This unit provides a convenient scale for many practical applications - for instance, a typical kitchen faucet delivers 0.1-0.2 L/s, while building ventilation systems may require 50-200 L/s depending on occupancy and air quality requirements.
Converting CFM to L/s requires applying the conversion factor that accounts for both volume and time units:
Example:
Convert 100 CFM to L/s:
100 × 0.471947 = 47.1947 L/s
1 cubic foot per minute equals approximately 0.471947 liters per second.
Most building codes require at least 50 CFM (23.6 L/s) for standard bathrooms, with higher rates for larger spaces. The general rule is 1 CFM per square foot of bathroom area.
Use an anemometer to measure air velocity at a duct opening, then multiply velocity by the cross-sectional area to get CFM. Professional HVAC technicians use calibrated flow hoods for 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 account for this.
CFM is actual volumetric flow at current conditions, while SCFM (Standard Cubic Feet per Minute) is normalized to standard conditions (typically 68°F and 14.7 psi at sea level) for fair comparison.
Add up the CFM requirements of all tools you'll run simultaneously, then add 30% for safety margin. Most home workshops need 4-6 CFM (1.9-2.8 L/s), while professional shops may need 15-30 CFM (7-14 L/s).