> For the complete documentation index, see [llms.txt](https://docs.carto.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.carto.com/carto-for-developers/reference/carto-widgets-reference/models/getformula.md).
# getFormula
A Formula model is a data model that represents a single numerical statistic, such as an average or a count. Suitable for *headline* or *scorecard* type of visualizations.
## **Usage**
```typescript
const formula = await data.widgetSource.getFormula({
column: 'column_name',
operation: 'count',
// + operationExp for custom operations
// + base options...
});
```
## **Options**
The `getFormula` model inherits all options from the [base options](/carto-for-developers/reference/carto-widgets-reference/models.md#model-base-options), plus:
```typescript
export interface FormulaRequestOptions extends BaseRequestOptions {
column: string | '*' | '';
operation: 'count' | 'avg' | 'min' | 'max' | 'sum' | 'custom' ;
operationExp?: string;
}
```
* **column:** the name of the column that you will run the statistical operation on. It also accepts the `*` value, that will
* name of the column
* `*` for total row count , used with count in operation
* empty string, in combination with custom + operationExp
* **operation:** the statistical operation that will be performed on the column. Accepted values are:
* `count`
* `avg`
* `min`
* `max`
* `sum`
* `custom`: a custom SQL expression, specified by `operationExp`.
* **operationExp** (optional): when using `operation: 'custom'` you need to specify the exact SQL operation that you want to run on your column. For example: `AVG(column_A) / AVG(column_B) * 100`.
## **Response**
A simple object containing the numerical value of the widget:
```typescript
type FormulaResponse = {value: number};
/* example response
{value: 1433230}
*/
```
The response can be then mapped to any HTML element, such as a scorecard.
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