Force Converter

Convert Newtons (N), Pounds-force (lbf), and Kilogram-force (kgf)

Last updated: 10/8/2026

Data sources:NIST Special Publication 811, Appendix B: Conversion factors

Enter a force in newtons, kilonewtons, pounds-force, or kilogram-force and the converter lists the same force in all four units. Pounds-force and kilogram-force are gravitational units: they are defined as the weight of one pound or one kilogram under standard gravity (9.80665 m/s²), which is why both factors contain that number.

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Conversion factors are exact definitions; the converter rounds displayed results to two decimals (four for kilonewtons).

How It Works

The value is first converted to newtons, then from newtons to each other unit. The exact definitions are 1 lbf = 4.448222 N (0.45359237 kg × 9.80665 m/s²), 1 kgf = 9.80665 N, and 1 kN = 1,000 N. Reversed: 1 N = 0.224809 lbf = 0.101972 kgf.

Mass is not force

A kilogram is a unit of mass; a kilogram-force is the force gravity exerts on that mass at standard gravity. On a scale calibrated in kg you read mass, but a load cell or spring balance measures force. A 10 kg object exerts 10 kgf = 98.07 N downward on Earth, and roughly 16.2 N on the Moon, while its mass stays 10 kg.

The same distinction applies to the pound: "lb" or "lbm" is mass, "lbf" is force. Engineering drawings in the US usually mean lbf when a load is quoted in pounds.

Worked example

Convert 250 lbf to newtons and kilogram-force

Newtons:250 lbf × 4.448222 N/lbf= 1,112.06 N

Kilonewtons:1,112.06 N ÷ 1,000= 1.1121 kN

Kilogram-force:1,112.06 N × 0.101972 kgf/N= 113.40 kgf

Tips & Best Practices

•Newtons (N) is the SI unit of force; kilonewtons are used for structural loads, anchors, and climbing gear ratings.
•Pounds-force (lbf) is common on US and UK specifications for thrust, tension, and load ratings.
•When a spec just says "pounds" or "kg" for a load or pull, it almost always means lbf or kgf.

Frequently Asked Questions

Why is 1 kgf equal to 9.80665 N and not 9.81 N?

Standard gravity is defined as exactly 9.80665 m/s², so the kilogram-force is defined as exactly 9.80665 N. Rounding to 9.81 introduces a 0.004% difference, which is irrelevant for most jobs but matters when converting large loads or calibrating instruments.