---
title: exponentialMovingAverage() function
description: exponentialMovingAverage() calculates the exponential moving average of n number of values in the _value column giving more weight to more recent data.
url: https://docs.influxdata.com/flux/v0/stdlib/universe/exponentialmovingaverage/
estimated_tokens: 2326
product: Flux
version: v0
---

# exponentialMovingAverage() function

-   Flux 0.37.0+
-   View InfluxDB support

`exponentialMovingAverage()` calculates the exponential moving average of `n` number of values in the `_value` column giving more weight to more recent data.

### Exponential moving average rules

-   The first value of an exponential moving average over `n` values is the algebraic mean of `n` values.
-   Subsequent values are calculated as `y(t) = x(t) * k + y(t-1) * (1 - k)`, where:
    -   `y(t)` is the exponential moving average at time `t`.
    -   `x(t)` is the value at time `t`.
    -   `k = 2 / (1 + n)`.
-   The average over a period populated by only `null` values is `null`.
-   Exponential moving averages skip `null` values.

##### Function type signature

```js
(<-tables: stream[{A with _value: B}], n: int) => stream[{A with _value: B}] where B: Numeric
```

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

## Parameters

### n

(Required) Number of values to average.

### tables

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

## Examples

-   [Calculate a three point exponential moving average](#calculate-a-three-point-exponential-moving-average)
-   [Calculate a three point exponential moving average with null values](#calculate-a-three-point-exponential-moving-average-with-null-values)

### Calculate a three point exponential moving average

```js
import "sampledata"

sampledata.int()
    |> exponentialMovingAverage(n: 3)
```

[](#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

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | 5 | t1 |
| 2021-01-01T00:00:30Z | 11 | t1 |
| 2021-01-01T00:00:40Z | 13 | t1 |
| 2021-01-01T00:00:50Z | 8.5 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | 6.666666666666667 | t2 |
| 2021-01-01T00:00:30Z | 12.833333333333334 | t2 |
| 2021-01-01T00:00:40Z | 12.916666666666668 | t2 |
| 2021-01-01T00:00:50Z | 6.958333333333334 | t2 |

### Calculate a three point exponential moving average with null values

```js
import "sampledata"

sampledata.int(includeNull: true)
    |> exponentialMovingAverage(n: 3)
```

[](#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 |  | t1 |
| 2021-01-01T00:00:20Z | 7 | t1 |
| 2021-01-01T00:00:30Z |  | t1 |
| 2021-01-01T00:00:40Z |  | t1 |
| 2021-01-01T00:00:50Z | 4 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:00Z |  | 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 |  | t2 |
| 2021-01-01T00:00:50Z | 1 | t2 |

#### Output data

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | 2.5 | t1 |
| 2021-01-01T00:00:30Z | 2.5 | t1 |
| 2021-01-01T00:00:40Z | 2.5 | t1 |
| 2021-01-01T00:00:50Z | 3.25 | t1 |

| _time | _value | *tag |
| --- | --- | --- |
| 2021-01-01T00:00:20Z | 0.5 | t2 |
| 2021-01-01T00:00:30Z | 9.75 | t2 |
| 2021-01-01T00:00:40Z | 9.75 | t2 |
| 2021-01-01T00:00:50Z | 5.375 | t2 |

#### Related

-   [movingAverage() function](/flux/v0/stdlib/universe/movingaverage/)
-   [timedMovingAverage() function](/flux/v0/stdlib/universe/timedmovingaverage/)
-   [doubleEMA() function](/flux/v0/stdlib/universe/doubleema/)
-   [tripleEMA() function](/flux/v0/stdlib/universe/tripleema/)
-   [InfluxQL EXPONENTIAL\_MOVING\_AVERAGE()](/influxdb/v1/query_language/functions/#exponential-moving-average)

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