A fishing rod bends deep and springs back; a steel rebar barely flexes at all. Young's modulus — the elastic modulus — puts a number on that personality: it is the tensile stress divided by the tensile strain. In symbols: E = σ / ε. Stress is force per area, strain is fractional stretch, and their ratio tells you how stiff the material is. Steel sits near 200 GPa, aluminum around 69 GPa, and rubber down near 0.01 GPa.

Engineers reach for E constantly. Sizing a cable for a deck railing, checking whether a 3D-printed bracket will hold its shape, or choosing between oak and pine for a workbench — stiffness decides, and E quantifies it. Because the modulus is a material property, one published number covers every shape: a steel wire and a steel I-beam share the same E, even though the beam is vastly harder to bend.

This calculator divides your test data into the modulus. Type the measured tensile stress in pascals in the Tensile Stress (σ, Pa) box and the measured strain as a decimal in the Tensile Strain (ε) box — 0.001 for a tenth of a percent stretch. The Young's Elastic Modulus (E, GPa) box reports gigapascals. A steel sample stressed to 200 MPa at 0.001 strain returns 200 GPa, right on the textbook value.

With the pre-filled defaults — Tensile Stress (σ, Pa) 200,000,000, Tensile Strain (ε) 0.001 — the Elastic Modulus Calculator returns Young's Elastic Modulus (E, GPa) 200.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.