Stress, Strain & Young's Modulus Calculator (Hooke's Law)

Stress is force divided by cross-sectional area, strain is the change in length divided by the original length, and Young's modulus is the ratio of the two in the elastic range. A 50 kN tensile load on a 200 mm² bar gives a stress of 50,000 ÷ 200 = 250 MPa. If a 500 mm gauge length stretches 0.6 mm, the strain is 0.6 ÷ 500 = 0.0012, so the modulus is 250 ÷ 0.0012 = about 208,000 MPa, or 208 GPa, which is typical of steel. Dividing the yield strength by the working stress gives the factor of safety: 350 ÷ 250 = 1.4. Results are only valid below the yield point, where the material returns to its original length when unloaded.