> ## Documentation Index
> Fetch the complete documentation index at: https://docs.wherobots.com/llms.txt
> Use this file to discover all available pages before exploring further.

# ST_Length

Returns the perimeter of A.

<Warning>
  Since `v1.7.0`, this function only supports LineString, MultiLineString, and GeometryCollections containing linear geometries. Use [ST\_Perimeter](/reference/wherobots-db/geometry-data/measurement/ST_Perimeter) for polygons.
</Warning>

<img src="https://mintcdn.com/wherobots/fqh3gPDE0J25Lra_/images/sql-functions/ST_Length/ST_Length.svg?fit=max&auto=format&n=fqh3gPDE0J25Lra_&q=85&s=c04ff35908800dc6372c6b03e5af57c4" alt="ST_Length" width="500" height="300" data-path="images/sql-functions/ST_Length/ST_Length.svg" />

## Signatures

```sql theme={"system"}
ST_Length (A: Geometry)
```

## Parameters

<ParamField body="A" type="Geometry" required>
  The input geometry.
</ParamField>

## Return type

<ResponseField type="Double">
  A numeric value.
</ResponseField>

## Example

```sql theme={"system"}
SELECT ST_Length(ST_GeomFromWKT('LINESTRING(38 16,38 50,65 50,66 16,38 16)'))
```

```
123.0147027033899
```