Convert Pound-force per Inch to Kilogram-force per Millimeter
Instantly convert Pound-force per Inch (lbf/in) to Kilogram-force per Millimeter (kgf/mm) with our free online calculator.
Formula: lbf/in to kgf/mm — multiply by 0.017858
Reference Table
| Pound-force per Inch (lbf/in) | Kilogram-force per Millimeter (kgf/mm) |
|---|---|
| 1 | 0.017858 |
| 5 | 0.0892899 |
| 10 | 0.17858 |
| 25 | 0.44645 |
| 50 | 0.892899 |
| 100 | 1.7858 |
How to Convert Pound-force per Inch to Kilogram-force per Millimeter
Formula
To convert Pound-force per Inch (lbf/in) to Kilogram-force per Millimeter (kgf/mm): multiply by 0.017858
Step-by-Step
- Start with your value in Pound-force per Inch (lbf/in).
- Multiply by 0.017858 to perform the conversion.
- The result is your value expressed in Kilogram-force per Millimeter (kgf/mm).
Conversion Factor
1 lbf/in = 0.017858 kgf/mm
Reverse Factor
1 kgf/mm = 55.9974 lbf/in
Worked Example
Convert 25 Pound-force per Inch to Kilogram-force per Millimeter: 25 lbf/in = 0.44645 kgf/mm
About Pound-force per Inch (lbf/in)
An imperial spring-rate unit equal to ≈ 175.127 N/m per NIST SP 811. lbf/in is dominant in US mechanical engineering for suspension and spring design: US automotive aftermarket coil springs (Eibach, Hyperco, Swift Spring, QA1 — typical passenger-car 150-300 lbf/in stock replacement; sport-tuning 350-800 lbf/in; race-car circle-track 1,000-3,000 lbf/in for front; oval-track on-power rear 1,200-2,800 lbf/in), trampoline springs (4-6 inch consumer trampoline ~75-150 lbf/in per spring, 96-spring trampolines reach effective bed rates 4,000-7,000 lbf/in), valve springs in internal-combustion engines per SAE J157 (typical OHV/OHC valve spring 175-500 lbf/in installed rate, beehive springs vary along travel), and machine-tool die springs per ISO 10243 / SAE J1426 standards. US spring-catalog datasheets (Lee Spring, Century Spring, McMaster-Carr) list stiffness in lbf/in. Convert lbf/in to N/m by multiplying by 175.127; to N/mm by multiplying by 0.1751.
About Kilogram-force per Millimeter (kgf/mm)
A legacy metric spring-rate unit equal to exactly 9,806.65 N/m ≈ 9.807 N/mm (derived from standard gravity g₀ = 9.80665 m/s² × 1 kg-mass = 9.80665 N-force per kgf). Although officially deprecated in favor of N/mm under ISO 80000, kgf/mm persists in specific contexts: older Japanese motorcycle and ATV service manuals (Yamaha, Suzuki, Kawasaki, Honda pre-2010 fork-spring and shock-spring rates dual-listed in kgf/mm alongside N/mm; e.g., a typical sport-bike fork spring rated 0.95 kgf/mm = 9.3 N/mm), industrial die-spring catalogs from Asian manufacturers (Misumi, Sankyo Oilless, Daiwa coiled-disc-spring assemblies), Korean automotive heavy-equipment shock-absorber and damper specs, and some legacy European mechanical-engineering documentation (especially older Italian and Spanish DIN-era industrial-machinery service manuals). Convert kgf/mm to N/mm by multiplying by exactly 9.80665; to lbf/in by multiplying by 56.005.
Quick Facts
- 1 Pound-force per Inch equals 0.017858 Kilogram-force per Millimeter
- 1 Kilogram-force per Millimeter equals 55.9974 Pound-force per Inch
- Pound-force per Inch is a unit of spring rate
- Kilogram-force per Millimeter is a unit of spring rate
- This conversion is commonly used in suspension design, mechanical design, and vibration analysis
- The Pound-force per Inch belongs to the imperial system
- The Kilogram-force per Millimeter belongs to the metric system
Common Pound-force per Inch to Kilogram-force per Millimeter Conversions
| Pound-force per Inch (lbf/in) | Kilogram-force per Millimeter (kgf/mm) |
|---|---|
| 0.01 | 0.00017858 |
| 0.1 | 0.0017858 |
| 0.25 | 0.0044645 |
| 0.5 | 0.00892899 |
| 1 | 0.017858 |
| 2 | 0.035716 |
| 3 | 0.053574 |
| 5 | 0.0892899 |
| 10 | 0.17858 |
| 15 | 0.26787 |
| 20 | 0.35716 |
| 25 | 0.44645 |
| 50 | 0.892899 |
| 75 | 1.33935 |
| 100 | 1.7858 |
| 250 | 4.4645 |
| 500 | 8.92899 |
| 1000 | 17.858 |
| 5000 | 89.2899 |
| 10000 | 178.58 |
Understanding Pound-force per Inch
The Pound-force per Inch (symbol: lbf/in) is a unit of spring rate. An imperial spring-rate unit equal to ≈ 175.127 N/m per NIST SP 811. lbf/in is dominant in US mechanical engineering for suspension and spring design: US automotive aftermarket coil springs (Eibach, Hyperco, Swift Spring, QA1 — typical passenger-car 150-300 lbf/in stock replacement; sport-tuning 350-800 lbf/in; race-car circle-track 1,000-3,000 lbf/in for front; oval-track on-power rear 1,200-2,800 lbf/in), trampoline springs (4-6 inch consumer trampoline ~75-150 lbf/in per spring, 96-spring trampolines reach effective bed rates 4,000-7,000 lbf/in), valve springs in internal-combustion engines per SAE J157 (typical OHV/OHC valve spring 175-500 lbf/in installed rate, beehive springs vary along travel), and machine-tool die springs per ISO 10243 / SAE J1426 standards. US spring-catalog datasheets (Lee Spring, Century Spring, McMaster-Carr) list stiffness in lbf/in. Convert lbf/in to N/m by multiplying by 175.127; to N/mm by multiplying by 0.1751.
It belongs to the imperial measurement system.
Pound-force per Inch are commonly used in suspension design, mechanical design, and vibration analysis.
Understanding Kilogram-force per Millimeter
The Kilogram-force per Millimeter (symbol: kgf/mm) is a unit of spring rate. A legacy metric spring-rate unit equal to exactly 9,806.65 N/m ≈ 9.807 N/mm (derived from standard gravity g₀ = 9.80665 m/s² × 1 kg-mass = 9.80665 N-force per kgf). Although officially deprecated in favor of N/mm under ISO 80000, kgf/mm persists in specific contexts: older Japanese motorcycle and ATV service manuals (Yamaha, Suzuki, Kawasaki, Honda pre-2010 fork-spring and shock-spring rates dual-listed in kgf/mm alongside N/mm; e.g., a typical sport-bike fork spring rated 0.95 kgf/mm = 9.3 N/mm), industrial die-spring catalogs from Asian manufacturers (Misumi, Sankyo Oilless, Daiwa coiled-disc-spring assemblies), Korean automotive heavy-equipment shock-absorber and damper specs, and some legacy European mechanical-engineering documentation (especially older Italian and Spanish DIN-era industrial-machinery service manuals). Convert kgf/mm to N/mm by multiplying by exactly 9.80665; to lbf/in by multiplying by 56.005.
It belongs to the metric measurement system.
Kilogram-force per Millimeter are commonly used in suspension design, mechanical design, and vibration analysis.
Why Convert Pound-force per Inch to Kilogram-force per Millimeter?
Converting between Pound-force per Inch and Kilogram-force per Millimeter is a frequent requirement for engineers, scientists, and students working with spring rate values. Different industries and regions favour different unit systems, so having a dependable conversion tool saves time and prevents errors in technical calculations. Whether you are verifying a specification sheet, cross-checking simulation results, or preparing a report for an international audience, accurate spring rate conversion is essential.
Frequently Asked Questions
How do I convert Pound-force per Inch to Kilogram-force per Millimeter?
An imperial spring-rate unit equal to ≈ 175. To convert Pound-force per Inch to Kilogram-force per Millimeter, multiply by 0.017858. For example, 25 lbf/in equals 0.44645 kgf/mm.
How many Kilogram-force per Millimeter are in 1 Pound-force per Inch?
There are 0.017858 Kilogram-force per Millimeter in 1 Pound-force per Inch.
How many Pound-force per Inch are in 1 Kilogram-force per Millimeter?
There are 55.9974 Pound-force per Inch in 1 Kilogram-force per Millimeter.
What is the formula for Pound-force per Inch to Kilogram-force per Millimeter conversion?
The formula is: multiply by 0.017858. This means 1 lbf/in = 0.017858 kgf/mm.
Is a Pound-force per Inch bigger than a Kilogram-force per Millimeter?
Yes. One Pound-force per Inch is larger than one Kilogram-force per Millimeter because 1 lbf/in equals 0.017858 kgf/mm, which is less than 1.
When do you need to convert between Pound-force per Inch and Kilogram-force per Millimeter?
A legacy metric spring-rate unit equal to exactly 9,806. Pound-force per Inch and Kilogram-force per Millimeter are both spring rate units, so conversion comes up whenever one source of information uses one unit and another uses the other — a classic cross-reference challenge in engineering, trade, travel, and everyday life.