---
title: math.log10() function
description: >
  `math.log10()` returns the decimal logarithm of x.
menu:
  flux_v0_ref:
    name: math.log10
    parent: math
    identifier: math/log10
weight: 101
---

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`math.log10()` returns the decimal logarithm of x.



##### Function type signature

```js
(x: float) => float
```

{{% caption %}}
For more information, see [Function type signatures](/flux/v0/function-type-signatures/).
{{% /caption %}}

## Parameters

### x
({{< req >}})
Value to operate on.




## Examples

- [Return the decimal lagarithm of a value](#return-the-decimal-lagarithm-of-a-value)
- [Use math.log10 in map](#use-mathlog10-in-map)

### Return the decimal lagarithm of a value

```js
import "math"

math.log10(x: 3.14)// 0.4969296480732149


```


### Use math.log10 in map

```js
import "sampledata"
import "math"

sampledata.float()
    |> map(fn: (r) => ({r with _value: math.log10(x: r._value)}))

```