# LN10 Constant

Use LN10 in Calcul.io. See what this built-in constant represents, enter it in an editable calculation, and review related values and units.

## LN10

Try it yourself:

```calculio
LN10
log(10)
```

---

## LN10: natural logarithm of ten

**LN10** is ln(10), approximately 2.302585. It converts between natural-logarithm and base-10 logarithm expressions.

## Practical use

Use [log()](https://calcul.io/function/log/index.md) for natural logarithms and [log10()](https://calcul.io/function/log10/index.md) for base-10 values. LN10 appears in the identity ln(x) = LN10 × log10(x).

## Caveat

Logarithms of real values require positive arguments. Preserve the constant exactly until final numeric output with [numeric()](https://calcul.io/function/numeric/index.md).

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