Spring Rate Converter

Why Convert Spring Rate Units?

Spring stiffness is quoted in different units depending on industry and region. European specs use N/m or N/mm; US automotive data often uses lb/in; some Asian catalogs list kgf/mm. Converting lets you compare springs and match replacements accurately.

Common Spring Rate Units

This converter supports N/m, kN/m, N/mm, lb/in, and kgf/mm. All values are normalized through N/m, the SI stiffness unit.

Useful relationships:

• 1 N/mm = 1000 N/m
• 1 kN/m = 1000 N/m
• 1 lb/in ≈ 175.13 N/m
• 1 kgf/mm ≈ 9806.65 N/m

Example: 100 N/m ≈ 0.571 lb/in.

Choosing the Right Unit

Use N/m for physics homework and SI engineering. Use lb/in when comparing US aftermarket coil springs. Use N/mm or kgf/mm for compact industrial spring catalogs.

Related tools: Spring Rate Calculator and Force Converter.