Docs / Transformers / Math

# Math

Perform arithmetic on payload values.

## Ports

Inlet
Input (any)
Outlet
Output (number)

## Configuration

Parameter | Type | Default | Description
--- | --- | --- | ---
`expression` | text | — | A math expression. Use `{{key}}` to reference payload values. Supports `+`, `-`, `*`, `/`, `%`, and parentheses.
`outputKey` | text | `"result"` | The payload key where the computed number is stored.
`precision` | number | `-1` | Number of decimal places to round to. `-1` means no rounding.

## Output Payload

`result` The computed number (or the key name configured via `outputKey`).

## Example

← Template Map Keys →