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Force Unit Converter (N / kN / lbf / kgf / dyne)

Force shows up in many different units across physics, engineering and everyday tools: newtons (N) and kilonewtons (kN) in SI; pound-force (lbf) and ounce-force (ozf) in US mechanical engineering; kilogram-force (kgf, sometimes called kilopond) in older civil work; and dyne in CGS chemistry and physics. Enter any value and get every other unit instantly, plus an intuitive "weight on Earth" comparison.

Live value in every force unit

N Newton —
kN Kilonewton —
mN Millinewton —
lbf Pound-force —
kgf Kilogram-force (kilopond) —
ozf Ounce-force —
dyne Dyne —

Equivalent weight on Earth —

Tip: 1 kgf = 9.80665 N exactly (standard gravity g₀); 1 lbf ≈ 4.44822 N; 1 dyne = 10⁻⁵ N. A force of 100 N is roughly the weight of a 10.2 kg object on Earth.

  • N SI base unit — physics and engineering formulas
  • kN Structural engineering, bridge loads, crash forces
  • lbf US mechanical engineering, aircraft thrust, springs
  • kgf Older engineering, civil works, weighing scales
  • dyne CGS unit — surface tension, chemical physics
  • ozf Small parts, spring tolerances, tactile feel

—

Formula

1 N = 1 kg·m/s² (SI definition) 1 kN = 1000 N 1 mN = 0.001 N 1 kgf = 9.80665 N (exact, standard gravity g₀) 1 lbf = 4.4482216152605 N (international pound-force, exact) 1 ozf = 1/16 lbf ≈ 0.27801385 N 1 dyne = 10⁻⁵ N (CGS: 1 g·cm/s²)

Frequently asked

Why is 1 kgf so much bigger than 1 N if both are units of force?

Because they are defined differently. The newton (N) is strictly defined by F = m·a: 1 N is the force that accelerates 1 kg by 1 m/s². The kilogram-force (kgf) is "the weight of 1 kg under standard gravity," i.e. 1 kg × 9.80665 m/s² = 9.80665 N. When people say a parcel "weighs 5 kg", they actually mean 5 kgf of weight (≈ 49 N) — old engineering texts use kgf for exactly this reason. SI strongly encourages keeping mass (kg) and force (N) cleanly separate.

How do US foot-pounds (ft·lb) relate to the pound-force (lbf) here?

Foot-pounds (ft·lb) come in two meanings: as a unit of work/energy it means 1 lbf acting through 1 ft, equal to 1.3558 J; as a unit of torque it means 1 lbf with a 1 ft lever arm, equal to 1.3558 N·m. This tool covers force only — not energy or torque. Use the Torque Converter for ft·lb of torque, or the Energy Converter for ft·lb of work.

When do people actually need to convert force units in real life?

Common cases include: comparing engine and rocket thrust across US (lb of thrust) and metric (kN) datasheets; reading structural load tables (kN in Europe/Asia, kgf or tonf in older work); gym equipment specs (lbs of pull); spring and screw specs (ozf or N); chemistry surface-tension figures (mN/m or dyne/cm); drone thrust-to-weight (gf or N). If you buy industrial parts from US suppliers you will see lbf everywhere — warranty sheets typically quote both N and lbf side-by-side.

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