---
title: stderror() | Tiger Data Docs
description: Estimate the relative standard error of a hyperloglog
---

Since [1.3.0](https://github.com/timescale/timescaledb-toolkit/releases/tag/1.3.0)

Estimate the relative standard error of a `Hyperloglog`. For approximate relative errors by number of buckets, see the [relative errors section](/docs/reference/toolkit/approximate-count-distinct#approximate-relative-errors/index.md).

## Samples

Estimate the relative standard error of a hyperloglog named `hyperloglog`. The expected output is 0.011490485194281396.

```
SELECT stderror(hyperloglog(8192, data))
  FROM generate_series(1, 100000) data
```

Output:

```
stderror
----------------------
0.011490485194281396
```

## Arguments

The syntax is:

```
stderror(
    hyperloglog Hyperloglog
) RETURNS DOUBLE PRECISION
```

| Name          | Type        | Default | Required | Description                               |
| ------------- | ----------- | ------- | -------- | ----------------------------------------- |
| `hyperloglog` | Hyperloglog | -       | ✔        | The hyperloglog to estimate the error of. |

## Returns

| Column   | Type             | Description                                                 |
| -------- | ---------------- | ----------------------------------------------------------- |
| stderror | DOUBLE PRECISION | The approximate relative standard error of the hyperloglog. |