# Rate of Change Formula (Chart Controls)

The rate of change formula calculates the rate of price change compared with historical data. It differs from the Performance Formula in that it calculates the rate of change against a period of days prior to the current price. The output is a percentage.

This formula can also be used to calculate the rate of volume change.

## Formula Details

### Syntax

```
Chart.DataManipulator.FinancialFormula(
FinancialFormula.RateOfChange,
"Period",
"Price",
"Rate")
```

### Parameters

This formula takes one optional parameter.

- Period

Number of days prior to the current day. The formula uses the data from that day as a reference when calculating the current rate of change. The default value is**10**.

### Input Values

This formula takes one input Y value.

- Price

Price for which the rate of change is calculated. It can be any other data for which you wish to calculate the rate of change, such as volume.

### Output Value

This formula outputs one Y value.

- Rate

Rate of change indicator.

## Remarks

The Line chart type is a convenient chart type to display the formula output.

## Example

The following example takes input from Series1's Y value for the daily close price (Series1:Y4), and outputs the rate of change on Series3 (Series3:Y). It uses data from 5 days prior to the current date as the reference.

```
Chart1.DataManipulator.FinancialFormula (FinancialFormula.RateOfChange, 5, "Series1:Y4", "Series3:Y")
```

```
Chart1.DataManipulator.FinancialFormula (FinancialFormula.RateOfChange, 5, "Series1:Y4", "Series3:Y");
```

## See Also

#### Reference

System.Windows.Forms.DataVisualization.Charting

System.Web.UI.DataVisualization.Charting