---
title: Conversion functions
description: PromQL conversion functions in Elasticsearch that convert between scalars and instant vectors.
url: https://www.elastic.co/elastic/docs-builder/docs/3562/reference/query-languages/promql/functions/conversion
products:
  - Elasticsearch
applies_to:
  - Elastic Cloud Serverless: Generally available
  - Elastic Stack: Preview in 9.4
---

# Conversion functions
These functions convert between scalars and instant vectors.

## `scalar`

<applies-to>Elastic Stack: Preview in 9.4</applies-to>
Returns the sample value of a single-element instant vector as a scalar. If the input vector does not have exactly one element, scalar returns NaN.
**Return type**
`scalar`
**Parameters**
<definitions>
  <definition term="v (instant_vector)">
    Instant vector input.
  </definition>
</definitions>

**Example**
```
scalar(sum(http_requests_total))
```


## `vector`

<applies-to>Elastic Stack: Preview in 9.4</applies-to>
Returns the scalar as a vector with no labels.
**Return type**
`instant_vector`
**Parameters**
<definitions>
  <definition term="s (scalar)">
    Scalar value.
  </definition>
</definitions>

**Example**
```
vector(1)
```