PSI to kN/mm² Converter

By: Patrick Myers Patrick Myers is the CEO and Founder of Calculator Academy. He has over eight years of experience developing online calculators and holds a B.S. in Mechanical Engineering. His work focuses on formula implementation, calculator accuracy, unit conversions, and creating practical tools that are easy to use.

Last Updated: July 6, 2026
Customize This Calculator or Create Your Own More Physics Calculators Community Calculators

This calculator was built with Calculator Academy’s community calculator studio with AI assistance, and was reviewed by the Calculator Academy team before publication.

About the PSI to kN/mm² Converter

This converter changes a pressure or stress value entered in PSI into kilonewtons per square millimeter. It is useful for engineers, students, and technicians working with material strength, hydraulic pressure, or structural stress values across imperial and metric units.

How to use this calculator

  1. Enter the pressure or stress value in the PSI input field.
  2. Review the converted value shown in kN/mm².
  3. Check the scientific notation result for very small or large converted values.
  4. Use the equivalent MPa value if you also need megapascals.
  5. Change the PSI input at any time to instantly update all results.

How it works

The calculator uses the entered PSI value as the only input. PSI means pounds per square inch, while kN/mm² means kilonewtons per square millimeter, both of which can describe pressure or stress.

The conversion formula is kN/mm² = PSI × 0.000006894757293168. This factor comes from the exact relationship 1 PSI = 6,894.757293168 pascals and 1 kN/mm² = 1,000,000,000 pascals.

The calculator also reports the same converted kN/mm² value in scientific notation and shows the equivalent value in MPa using MPa = PSI × 0.006894757293168. Results are unit-conversion estimates based on the entered numeric value and do not account for material behavior, safety factors, or design-code requirements.

Example calculation

For an input of 1,000 PSI, multiply 1,000 by 0.000006894757293168. The result is 0.006894757293168 kN/mm², displayed as about 0.00689476 kN/mm², or 6.89476 × 10⁻³ in scientific notation. The equivalent pressure is 6.89476 MPa.

Frequently asked questions

How many kN/mm² are in 1 PSI?

1 PSI equals 0.000006894757293168 kN/mm².

Is kN/mm² the same as GPa?

Yes. Because 1 kN/mm² equals 1 GPa, a converted value in kN/mm² has the same numeric value in GPa.

How do I convert PSI to MPa?

Multiply PSI by 0.006894757293168. The calculator shows this MPa equivalent along with the kN/mm² result.

Can this be used for both pressure and stress?

Yes. PSI and kN/mm² are both force-per-area units, so the conversion applies to pressure, tensile stress, compressive stress, and similar quantities.