---
title: stddev() function
description: stddev() returns the standard deviation of non-null values in a specified column.
url: https://docs.influxdata.com/flux/v0/stdlib/universe/stddev/
estimated_tokens: 1230
product: Flux
version: v0
---

# stddev() function

-   Flux 0.7.0+
-   View InfluxDB support

`stddev()` returns the standard deviation of non-null values in a specified column.

##### Function type signature

```js
(<-tables: stream[A], ?column: string, ?mode: string) => stream[B] where A: Record, B: Record
```

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

## Parameters

### column

Column to operate on. Default is `_value`.

### mode

Standard deviation mode or type of standard deviation to calculate. Default is `sample`.

**Available modes:**

-   **sample**: Calculate the sample standard deviation where the data is considered part of a larger population.
-   **population**: Calculate the population standard deviation where the data is considered a population of its own.

### tables

Input data. Default is piped-forward data (`<-`).

## Examples

### Return the standard deviation of values in each table

```js
import "sampledata"

sampledata.int()
    |> stddev()
```

[](#view-example-input-and-output)

View example input and output

#### Input data

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | -2 | t1 |
| 2021-01-01T00:00:10Z | 10 | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z | 17 | t1 |
| 2021-01-01T00:00:40Z | 15 | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z | 19 | t2 |
| 2021-01-01T00:00:10Z | 4 | t2 |
| 2021-01-01T00:00:20Z | -3 | t2 |
| 2021-01-01T00:00:30Z | 19 | t2 |
| 2021-01-01T00:00:40Z | 13 | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| *tag | _value |
| --- | --- |
| t1 | 7.063993204979744 |

| *tag | _value |
| --- | --- |
| t2 | 9.474527252938094 |

#### Related

-   [InfluxQL – STDDEV()](/influxdb/v1/query_language/functions/#stddev)
-   [experimental.stddev() function](/flux/v0/stdlib/experimental/stddev/)

[transformations](/flux/v0/tags/transformations/) [aggregates](/flux/v0/tags/aggregates/)