> For the complete documentation index, see [llms.txt](https://docs.fabricplan.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fabricplan.com/documentation/plan/planning-sheets/formula-syntax/text-formatting-functions/replace.md).

# REPLACE

The *REPLACE* function replaces part of a text string with another text value based on the specified position and length. The index starts at 1, where the first character in the text string has an index of 1.

#### Syntax

```javascript
REPLACE(old_string, index, length, replace_text)
```

#### Arguments

* `old_string`: The original text string.
* `index`: The starting position of the characters to replace.
* `length`: The number of characters to replace.
* `replace_text`: The text string that replaces the specified characters.

#### Return value

Returns the updated text string after replacement.

#### Example

```javascript
REPLACE("Sales_US", 7, 2, "UK")
```

Returns `Sales_UK`.

#### Excel equivalent

[REPLACE](https://support.microsoft.com/en-us/office/replace-function-8d799074-2425-4a8a-84bc-82472868878a)

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