---
id: "M:cAlgo.API.Internals.IIndicatorsAccessor.StandardDeviation(cAlgo.API.DataSeries,System.Int32,cAlgo.API.MovingAverageType)"
kind: "method"
type: "T:cAlgo.API.Internals.IIndicatorsAccessor"
url: "https://help.ctrader.com/ctrader-algo/references/Indicators/IIndicatorsAccessor/StandardDeviation/"
---

> Documentation index for agents: https://help.ctrader.com/ctrader-algo/llms.txt · machine index: https://help.ctrader.com/ctrader-algo/api.json

# IIndicatorsAccessor.StandardDeviation

Member of [IIndicatorsAccessor](https://help.ctrader.com/ctrader-algo/references/Indicators/IIndicatorsAccessor/index.md).

## StandardDeviation(DataSeries source, int periods, MovingAverageType maType)

The Standard Deviation indicator shows volatility.

Environments: Desktop supported · CLI supported · Cloud supported.

C#:

```csharp
StandardDeviation StandardDeviation(DataSeries source, int periods, MovingAverageType maType)
```

Python:

```python
api.Indicators.StandardDeviation(source: DataSeries, periods: int, maType: MovingAverageType) -> StandardDeviation
```

### Parameters

- `source` (`DataSeries`, Python `DataSeries`): The source data used for calculation.
- `periods` (`int`, Python `int`): The value of the periods used for calculation.
- `maType` (`MovingAverageType`, Python `MovingAverageType`): Type of the Moving Average.

### Returns

`StandardDeviation` — Standard Deviation indicator instance

### Examples

C#:

```csharp
var standardDeviation = Indicators.StandardDeviation(Bars.ClosePrices, 20, MovingAverageType.Simple);
if (standardDeviation.Result.Last(1) > standardDeviation.Result.Last(2))
    Print("Volatility is increasing: {0}", standardDeviation.Result.Last(1));
```

Python:

```python
standardDeviation = api.Indicators.StandardDeviation(api.Bars.ClosePrices, 20, MovingAverageType.Simple)
if standardDeviation.Result.Last(1) > standardDeviation.Result.Last(2):
    api.Print(f"Volatility is increasing: {standardDeviation.Result.Last(1)}")
```