docs-v2/content/v2.0/query-data/flux/cumulativesum.md

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---
title: Query cumulative sum
seotitle: Query cumulative sum in Flux
list_title: Cumulative sum
description: >
Use the `cumulativeSum()` function to calculate a running total of values.
weight: 210
menu:
v2_0:
parent: Query with Flux
name: Cumulative sum
v2.0/tags: [query, cumulative sum]
related:
- /v2.0/reference/flux/stdlib/built-in/transformations/cumulativesum/
list_query_example: cumulative_sum
---
Use the [`cumulativeSum()` function](/v2.0/reference/flux/stdlib/built-in/transformations/cumulativesum/)
to calculate a running total of values.
`cumulativeSum` sums the values of subsequent records and returns each row updated with the summed total.
{{< flex >}}
{{% flex-content "half" %}}
**Given the following input table:**
| _time | _value |
| ----- |:------:|
| 0001 | 1 |
| 0002 | 2 |
| 0003 | 1 |
| 0004 | 3 |
{{% /flex-content %}}
{{% flex-content "half" %}}
**`cumulativeSum()` returns:**
| _time | _value |
| ----- |:------:|
| 0001 | 1 |
| 0002 | 3 |
| 0003 | 4 |
| 0004 | 7 |
{{% /flex-content %}}
{{< /flex >}}
{{% note %}}
The examples below use the [example data variable](/v2.0/query-data/flux/#example-data-variable).
{{% /note %}}
##### Calculate the running total of values
```js
data
|> cumulativeSum()
```
## Use cumulativeSum() with aggregateWindow()
[`aggregateWindow()`](/v2.0/reference/flux/stdlib/built-in/transformations/aggregates/aggregatewindow/)
segments data into windows of time, aggregates data in each window into a single
point, then removes the time-based segmentation.
It is primarily used to [downsample data](/v2.0/process-data/common-tasks/downsample-data/).
`aggregateWindow()` expects an aggregate function that returns a single row for each time window.
To use `cumulativeSum()` with `aggregateWindow`, use `sum` in `aggregateWindow()`,
then calculate the running total of the aggregate values with `cumulativeSum()`.
<!-- -->
```js
data
|> aggregateWindow(every: 5m, fn: sum)
|> cumulativeSum()
```