Convert Cubic Feet per Minute to Liters per Second

Formula

L/s = CFM × 0.4719474432

or L/s = CFM ÷ 2.118880003289

Derivation from SI units:

• 1 CFM = (0.3048 m)³ ÷ 60 s = 4.719474432 × 10⁻⁴ m³/s
• 1 L/s = 10⁻³ m³ ÷ 1 s
• 1 CFM = 0.0004719474432 m³/s ÷ 0.001 m³/s per L/s = 0.4719474432 L/s

Both units are defined exactly, so the factor is exact. Cubic Foot per Minute definition: cubic foot per minute; Liter per Second definition: liter per second.

Worked examples

1. A classic outdoor-air rate of 15 CFM per person is 7.079211648 L/s.
   15 CFM × 0.4719474432 = 7.079211648 L/s
2. A bathroom exhaust fan rated 100 CFM extracts 47.19474432 L/s.
   100 CFM × 0.4719474432 = 47.19474432 L/s

Where it's used

Ventilation rates per person are given in CFM in US codes and in L/s in most other countries. One CFM is about 0.472 L/s.

Cubic Foot per Minute to other flow rate units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "cubic foot per minute (ft³/min)".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 8 (litre).

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.