A Japanese motorcycle manual specs spring stiffness in kgf/mm. I found a US spring in lbf/in. How do I tell if they're equivalent?

Convert to the same units. 1 kgf/mm = 2.2046 lbf/mm = 2.2046 ÷ 0.03937 ≈ 56 lbf/in. So a spring listed as 10 kgf/mm needs a US equivalent of about 560 lbf/in.

My pressure gauge reads in lbf/in² (psi). How do I compare that to a kgf/cm² specification?

1 kgf/cm² ≈ 14.22 psi. A Japanese pump rated at 100 kgf/cm² operates at roughly 1,422 psi. Alternatively, 1 psi ÷ 14.22 ≈ 0.0703 kgf/cm².

Why do some countries use kgf instead of newtons?

Kilogram-force was historically intuitive — 1 kgf is the downward force of a 1 kg mass, easy to visualize. SI standardization replaced it with newtons in most new contexts, but kgf persists in Japanese, Korean, and some European industrial documents decades after SI adoption.

My hydraulic jack is rated at 10,000 lbf. Can I use it to lift a load with a 4,500 kgf static weight?

4,500 kgf × (1 ÷ 0.4536) = 4,500 ÷ 0.4536 ≈ 9,921 lbf. Your jack's 10,000 lbf rating exceeds the 9,921 lbf load, giving you about a 0.8% margin — very thin. Add a safety factor and use a higher-rated jack.

Pound-Force (lbf) to Kilogram-Force (kgf) Converter

Enter a value to instantly convert between force units.

From

Precision4 dp

1 Pound-Force = 0.4536 Kilogram-Force

Key Formulas

Newton → Pound-Force

lbf = N × 0.224809

Pound-Force → Newton

N = lbf × 4.44822

Kilogram-Force → Newton

N = kgf × 9.80665

Newton → Kilogram-Force

kgf = N × 0.101972

Formula

kgf = lbf × 0.45359237

US-made equipment — torque wrenches, hydraulic cylinders, rigging hardware — carries lbf ratings, while the machinery it interfaces with in Asian or European factories specifies limits in kgf. A US crane hook rated at 2,000 lbf feeding a Japanese gantry rated at 900 kgf, or an American spring supplier's product being specified for a Korean assembly line, requires this conversion to confirm compatibility. The 0.4536 factor is simply the number of kilograms per pound.

Source: NIST SP 811, Table B.8

Last reviewed: 2026-06-11 · see our methodology

Frequently Asked Questions

Real-World Examples

The weight of 1 lb in metric force — a calibration reference when verifying a US pound-rated hanging scale against a metric kgf standard.

1 lbf = 0.454 kgf

A US rigging sling rated at 100 lbf — approximately 45.4 kgf, checked against a Korean machine's 50 kgf attachment point limit.

100 lbf = 45.36 kgf

A US torque specification of 220 lbf — approximately 100 kgf, the design limit stamped on a Japanese automotive assembly fixture.

220 lbf = 99.79 kgf

One metric ton-force (1,000 kgf) expressed in lbf — a reference anchor when comparing US cable working load limits against metric lift points.

2205 lbf = 1000 kgf

newtons to lbf lbf to newtons kgf to newtons newtons to kgf kn to newtons newtons to kn

Pound-Force (lbf) to Kilogram-Force (kgf) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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