I need a replacement spring rated at 50 ozf. A metric supplier lists springs in kgf. What should I order?

50 × 0.02835 ≈ 1.42 kgf. Order a 1.4 or 1.5 kgf spring. Also verify the spring's stiffness (rate, in kgf/mm) matches the original — same peak force doesn't guarantee identical spring behavior.

My hobby servo says '60 g·cm torque' on the spec sheet. Is that the same as ozf?

Not directly. 'g·cm' is gram-force × centimetre (a torque unit). 60 g·cm = 0.06 kgf·cm = 0.06 × 35.27 ozf·cm ≈ 2.12 ozf·cm. To convert torque properly, use a torque converter — this force converter handles force only.

Is there a quick mental math for ozf to kgf?

Roughly: divide ozf by 35. One kgf ≈ 35 ozf. For 70 ozf: 70 ÷ 35 = 2 kgf. The exact factor gives 70 × 0.02835 = 1.985 kgf — about 0.7% off.

Is kgf still used in modern engineering, or should everything be in newtons?

SI (newtons) is the modern standard. kgf persists in Japanese automotive and industrial documentation, older European machinery, and Asian spring catalogs. When sourcing parts internationally, you'll still encounter kgf regularly.

Ounce-Force (ozf) to Kilogram-Force (kgf) Converter

Enter a value to instantly convert between force units.

From

Precision4 dp

1 Ounce-Force = 0.0283 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 = ozf × 0.0283495231

Light precision instruments — clock springs, postal scale mechanisms, hobby servo motors — are rated in ozf in US and UK markets but in kgf by Asian and European suppliers. When a watchmaker needs a metric replacement for a 50 ozf mainspring, or a product engineer must match a US spring catalog spec to a Japanese assembly drawing, converting ozf to kgf is the daily bridge. The 0.02835 factor comes directly from 1 oz = 0.02835 kg, applied as force.

Source: NIST SP 811, Table B.8

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

Frequently Asked Questions

Real-World Examples

One pound-force (16 ozf) in kgf — the anchor value showing that 0.454 kg mass corresponds to 0.454 kgf, consistent with the pound-to-kilogram mass conversion.

16 ozf = 0.4536 kgf

A clock mainspring rated at 50 ozf — 1.42 kgf, the value used when ordering a metric replacement spring from a Swiss catalog.

50 ozf = 1.417 kgf

A '5 lb test' fishing line (80 ozf breaking strength) — 2.27 kgf, the rated pull force for comparison against a Japanese scale's kgf capacity.

80 ozf = 2.268 kgf

One ounce-force — 0.02835 kgf, the force exerted by a 28.35 g calibration weight under standard gravity.

1 ozf = 0.02835 kgf

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

Ounce-Force (ozf) to Kilogram-Force (kgf) Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

Related Converters