If a cylinder specimen is used to test the compressive strength of concrete, the equivalent cube strength can be found using:

🔄 Converting Cylinder Strength to Equivalent Cube Strength

Standard cylinder specimens (typically 150 mm dia × 300 mm height) give a lower apparent strength than 150 mm cubes because the height-to-diameter ratio allows more lateral deformation and friction effects are smaller. Empirically:

Cylinder strength ≈ 0.8 × Cube strength

Rearranging to get the equivalent cube strength:

Cube strength = Cylinder strength / 0.8 = (5/4) × Cylinder strength

Key takeaway

Cylinder is ~80% of cube strength, so multiply cylinder result by 5/4 to get the cube equivalent.