> ## Documentation Index
> Fetch the complete documentation index at: https://docs.anlytic.com/llms.txt
> Use this file to discover all available pages before exploring further.

# CumulativeStdDev

Calculates the cumulative standard deviation of values from the first row up to the current row within a partition.

**Category:** `window`

**Syntax:**

```
CumulativeStdDev([column])
```

**Returns:** `Float`

**Context Filtering:** ✓ Yes

## Parameters

| Name     | Type     | Required | Description                                                       |
| -------- | -------- | -------- | ----------------------------------------------------------------- |
| `column` | `column` | ✓ Yes    | The numeric column to calculate cumulative standard deviation for |

**Allowed Column Types for `column`:** INT, FLOAT, DECIMAL, NUMBER

## Validation

* Minimum parameters: 1
* Maximum parameters: 1

## Examples

```
CumulativeStdDev([Sales])
```

Returns the running standard deviation of sales from the first row to the current row.

```
CumulativeStdDev([Response_Time])
```

Calculates cumulative standard deviation of response times, useful for tracking variability over time.

## Related Functions

* [CumulativeVariance](cumulativevariance) - Calculates cumulative variance
* [MovingStdDev](movingstddev) - Calculates moving standard deviation with a window
* [StDev](../aggregate/stdev) - Returns the overall standard deviation
* [CumulativeAvg](cumulativeavg) - Calculates cumulative average