# SQRT2 Constant

Use SQRT2 in Calcul.io. See what this built-in constant represents, enter it in an editable calculation, and review related values and units.

## SQRT2

Try it yourself:

```calculio
SQRT2
sqrt(2)
```

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## SQRT2: the square root of two

**SQRT2** is the dimensionless constant √2, the diagonal length of a unit square. It is irrational and frequently appears in geometry, normalization, and trigonometry.

## Use

Use it for 45-degree relationships and compare it with [SQRT1_2](https://calcul.io/constants/SQRT1_2/index.md), its reciprocal. [sqrt](https://calcul.io/function/sqrt/index.md) computes roots generally, while [pow](https://calcul.io/function/pow/index.md) verifies the square.

## Caveats

Decimal output is approximate. Keep the symbolic constant when exact cancellation matters, and use [simplify](https://calcul.io/function/simplify/index.md) for algebraic reduction.

[All constants](https://calcul.io/constants/index.md)