---
title: promql.instantRate() function
description: promql.instantRate() is a helper function that calculates instant rates over counters and is used to implement PromQL’s irate() and idelta() functions.
url: https://docs.influxdata.com/flux/v0/stdlib/internal/promql/instantrate/
estimated_tokens: 519
product: Flux
version: v0
---

# promql.instantRate() function

-   Flux 0.47.0+
-   View InfluxDB support

`promql.instantRate()` is a helper function that calculates instant rates over counters and is used to implement PromQL’s [`irate()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#irate) and [`idelta()`](https://prometheus.io/docs/prometheus/latest/querying/functions/#idelta) functions.

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

##### Function type signature

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

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

## Parameters

### tables

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

### isRate

Data represents a rate.