This free tensile strength converter from HAGUE FASTENERS LIMITED converts stress and strength between MPa, N/mm², GPa, psi, ksi, UK tons per square inch, kgf/mm², kgf/cm² and bar. Switch the menu to convert force and load (N, kN, lbf, kip, kgf, tonnes and UK tons) or tightening torque (N m, lbf ft, lbf in and kgf m).
Stress, force and torque converter
Tons are UK long tons-force (2,240 lbf); tonnes are metric tonnes-force (1,000 kgf). 1 MPa = 1 N/mm².
Guidance only. Results are approximate and for initial guidance. They are not a substitute for the governing standard, specification or drawing, or for testing. HAGUE FASTENERS LIMITED accepts no liability for decisions made using these tools. Always check critical values against the relevant standard. © 2026 HAGUE FASTENERS LIMITED.
How to use the converter
- Choose stress and strength, force and load, or torque.
- Enter the value and choose the unit it is in.
- Read the value in every other unit. The unit you entered is outlined in gold.
Useful conversions for fastener engineers
- 1 MPa = 1 N/mm²
- 1 ksi = 1,000 psi = 6.895 MPa
- 1 UK ton per square inch = 15.444 MPa
- 1 kgf/mm² = 9.807 MPa
- Property class 8.8 (800 MPa nominal tensile) is about 116 ksi
- ASTM A193 B7 (up to 2 1/2″) has a minimum tensile strength of 125 ksi, about 862 MPa
Mixed units are common when one job brings together American, European and older British drawings. Converting each figure the same way, with enough decimal places, avoids rounding errors creeping into a purchase order or inspection report.
Frequently asked questions
Is N/mm² the same as MPa?
Yes. One newton per square millimetre is exactly one megapascal, so the numbers are the same.
What is a ton per square inch?
Older British drawings and standards give strength in tons per square inch, using the long ton of 2,240 lb. One ton per square inch is 15.444 MPa. Do not confuse it with the US short ton or the metric tonne, which are different.
Can I convert hardness to tensile strength here?
Use our hardness converter, which gives an approximate tensile strength from a hardness reading.
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