---
title: rate() | Tiger Data Docs
description: Calculate the rate of change from a gauge aggregate
---

Early access [1.6.0](https://github.com/timescale/timescaledb-toolkit/releases/tag/1.6.0)

Calculate the rate of change of the gauge. This is the simple rate, equal to the last value minus the first value, divided by the time elapsed.

## Samples

Get the rate of change per `id` over the entire recorded interval.

```
SELECT
    id,
    rate(summary)
FROM (
    SELECT
        id,
        gauge_agg(ts, val) AS summary
    FROM foo
    GROUP BY id
) t
```

## Arguments

The syntax is:

```
rate(
    summary GaugeSummary
) RETURNS DOUBLE PRECISION
```

| Name      | Type           | Default | Required | Description                                                                                                             |
| --------- | -------------- | ------- | -------- | ----------------------------------------------------------------------------------------------------------------------- |
| `summary` | `GaugeSummary` | -       | ✔        | A gauge aggregate created using [`gauge_agg`](/docs/reference/toolkit/counters-and-gauges/gauge_agg/gauge_agg/index.md) |

## Returns

| Column | Type             | Description                     |
| ------ | ---------------- | ------------------------------- |
| rate   | DOUBLE PRECISION | The rate of change of the gauge |