---
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: 698
product: Flux
version: v0
publisher: InfluxData
canonical: https://docs.influxdata.com/flux/v0/stdlib/universe/stddev/
date: '2024-04-08T16:01:02-06:00'
lastmod: '2024-04-08T16:01:02-06:00'
---

* Flux 0.7.0+

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/)
| _time | _value | *tag |
| --- | --- | --- |
| _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 |
| --- | --- | --- |
| _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 |

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

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