What Is a Kilonewton (kN)?

A kilonewton is exactly 1000 newtons. The prefix "kilo" means one thousand, as in kilogram and kilometer.

The symbol is kN, with a lowercase k and a capital N. A capital K is not an SI prefix, and "KN" or "Kn" are common but wrong spellings. The plural is kilonewtons; the symbol never takes an s.

Kilonewtons are convenient because everyday structural and equipment forces are thousands of newtons. Writing 12 kN is easier to read and check than 12 000 N.

One kilonewton is about 224.809 lbf or 101.97 kgf: roughly the weight of a 102 kg mass under standard gravity.

• Structural and civil engineering: loads on beams, columns, anchors and foundations.
• Fasteners and anchors: pull-out and shear ratings of bolts and wall anchors.
• Climbing and safety equipment: carabiners, slings and ropes are marked with strengths in kN. A 22 kN rating is about 4946 lbf.

• A force of 10 kN is 10000 N: multiply by 1000.
• A force of 10 kN is 2248.09 lbf.
• A force of 10 kN is 1019.72 kgf under standard gravity.
• A force of 4500 N is 4.5 kN: divide by 1000.

The prefix kilo means one thousand, so 1 kN = 1000 N exactly. Small forces are usually written in newtons, forces in the thousands in kilonewtons, and very large ones such as the thrust of a rocket engine or the load on a bridge support in meganewtons, where 1 MN = 1000 kN.

When you read a rating, check the prefix before converting. A rating given in kN is a thousand times larger than the same number in N.

• Reading kN as a mass. A strength of 10 kN is a force; the mass whose weight equals it is about 1020 kg under standard gravity.
• Confusing kN with kN/m². The first is a force, the second is a pressure or a distributed load (1 kN/m² = 1 kPa).
• Treating a breaking strength as a working load. Equipment ratings in kN are usually the force at which the part fails; the safe working load is lower and is set by the relevant standard.

Structural engineers also use the kilonewton meter (kN·m) for bending moments and torque. One kN·m is 1000 N·m, or about 737.562 lbf·ft.