Square root of 2: value, examples & calculator

The square root of 2, written √2 or SQRT2 in Calcul.io, is approximately 1.4142135623730951. It is the positive number whose square is 2.

√2 is irrational, so its decimal expansion never ends or repeats. The decimal above is a rounded approximation. To four decimal places, √2 ≈ 1.4142.

Worked example: the diagonal of a square

A square with sides of 5 cm has a diagonal of sqrt(5^2 + 5^2) cm by the Pythagorean theorem. Simplifying gives 5 * sqrt(2) cm, or approximately 7.0711 cm.

Use 5 cm * SQRT2 in the calculator below. Change the side length to calculate another square's diagonal.

Try the square root of 2 calculator

Click any line to edit it. SQRT2 and sqrt(2) give the same value; SQRT2^2 gives 2, subject to numerical precision.