---
title: ES|QL TO_DOUBLE function
description: 
url: https://www.elastic.co/docs/reference/query-languages/esql/functions-operators/type-conversion-functions/to_double
products:
  - Elasticsearch
---

# ES|QL TO_DOUBLE function
## Syntax

![Embedded](https://www.elastic.co/docs/reference/query-languages/esql/images/generated/x-pack-esql/functions/to_double.svg)


## Parameters

<definitions>
  <definition term="field">
    Input value. The input can be a single- or multi-valued column or an expression.
  </definition>
</definitions>


## Description

Converts an input value to a double value. If the input parameter is of a date type, its value will be interpreted as milliseconds since the [Unix epoch](https://en.wikipedia.org/wiki/Unix_time), converted to double. Boolean `true` will be converted to double `1.0`, `false` to `0.0`.

## Supported types


| field           | result |
|-----------------|--------|
| boolean         | double |
| counter_double  | double |
| counter_integer | double |
| counter_long    | double |
| date            | double |
| double          | double |
| integer         | double |
| keyword         | double |
| long            | double |
| text            | double |
| unsigned_long   | double |


## Example

```esql
ROW str1 = "5.20128E11", str2 = "foo"
| EVAL dbl = TO_DOUBLE("520128000000"), dbl1 = TO_DOUBLE(str1), dbl2 = TO_DOUBLE(str2)
```


| str1:keyword | str2:keyword | dbl:double | dbl1:double | dbl2:double |
|--------------|--------------|------------|-------------|-------------|
| 5.20128E11   | foo          | 5.20128E11 | 5.20128E11  | null        |

Note that in this example, the last conversion of the string isn’t possible.
When this happens, the result is a `null` value. In this case a _Warning_ header is added to the response.
The header will provide information on the source of the failure:
`"Line 1:115: evaluation of [TO_DOUBLE(str2)] failed, treating result as null. Only first 20 failures recorded."`
A following header will contain the failure reason and the offending value:
`"java.lang.NumberFormatException: For input string: "foo""`