---
title: promql.extrapolatedRate() function
description: promql.extrapolatedRate() is a helper function that calculates extrapolated rates over counters and is used to implement PromQL’s rate(), delta(), and increase() functions.
url: https://docs.influxdata.com/flux/v0/stdlib/internal/promql/extrapolatedrate/
estimated_tokens: 714
product: Flux
version: v0
---

# promql.extrapolatedRate() function

-   Flux 0.47.0+
-   View InfluxDB support

`promql.extrapolatedRate()` is a helper function that calculates extrapolated rates over counters and is used to implement PromQL’s [`rate()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#rate), [`delta()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#increase), and [`increase()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#delta) functions.

**Important**: The `internal/promql` package is not meant for external use.

##### Function type signature

```js
(
    <-tables: stream[{A with _value: float, _time: time, _stop: time, _start: time}],
    ?isCounter: bool,
    ?isRate: bool,
) => stream[{B with _value: float}]
```

For more information, see [Function type signatures](/flux/v0/function-type-signatures/).

## Parameters

### tables

Input data. Default is piped-forward data (`<-`).

### isCounter

Data represents a counter.

### isRate

Data represents a rate.