Pound-force to newtons (lbf to N)

The formula

N = lbf × 4.448221615

Where the factor comes from — each unit by its definition, then its size in SI:

• 1 lbf = lb × gₙ (standard gravity, CODATA 2022) × m / s² = 4.44822161526 N
• 1 N is the SI unit of force.

Dividing the two SI sizes gives the factor: 4.44822161526 (rounded for display; the underlying ratio is fixed by the definitions). The reverse factor is 0.2248089431.

Force in SI is the newton (kg·m/s²). Kilogram-force and pound-force are the weights of a kilogram and a pound at standard gravity — gravity's conventional value, not your local one.

Worked examples

• The weight of a 1 kg mass at standard gravity (1 kgf): 2.20462 lbf = 9.80665 N — 2.20462 × 4.448221615 = 9.80665
• A firm push: 22.4809 lbf = 100 N — 22.4809 × 4.448221615 = 100
• The weight of a 10 lb bag at standard gravity: 10 lbf = 44.4822 N — 10 × 4.448221615 = 44.4822
• A towing load (5 kN): 1,124.04 lbf = 5,000 N — 1,124.04 × 4.448221615 = 5,000

Frequently asked questions