---
title: "__eval"
description: "JMeter __eval function reference: syntax, parameters, and practical examples for parameterizing test plans with dynamic values."
url: https://docs.jmeter.ai/functions/eval/
lastUpdated: 2026-10-01
source: docs.jmeter.ai
---

# __eval

*Also documented in context in the [full Functions and Variables reference](/user-manual/functions/#__eval).*

The eval function returns the result of evaluating a string expression.

This allows one to interpolate variable and function references in a string
which is stored in a variable.    For example, given the following variables:

- `name`=`Smith`
- `column`=`age`
- `table`=`birthdays`
- `SQL`=`select \${column} from \${table} where name='\${name}'`

then `\${__eval(\${SQL})}` will evaluate as “`select age from birthdays where name='Smith'`”.

This can be used in conjunction with CSV Dataset, for example
where the both SQL statements and the values are defined in the data file.

| Name | Required | Description |
| --- | --- | --- |
| Variable name | Yes | The variable to be evaluated. |

## Related

- [Functions and Variables Guide](/topics/functions-and-variables/)
- [Regex Extractor Builder](/tools/regex-tester/)
- [Full Functions Reference](/user-manual/functions/)
- [Component Reference](/user-manual/component-reference/)