Find and replace

How to find and replace text

1. Paste your text into the input area.
2. Enter the text to find in the Find field.
3. Enter the replacement text in the Replace with field.
4. The result updates instantly. Enable Regex, Case sensitive, or Whole word options as needed.

Common uses

• Bulk editing repeated words or phrases in copied text before pasting elsewhere
• Using regex patterns to clean up log files, replace variable names, or reformat dates
• Working alongside a side-by-side comparison view to verify changes, or sorting and deduplicating the result afterward

Technical specification

• Algorithm or formula: Builds a JavaScript RegExp from the find term with the global and Unicode (u) flags. Plain mode escapes regex metacharacters; a regex that is only valid without u runs without it. Whole-word mode skips a match that has a letter, digit or underscore (in any script) directly before or after it; for a regex that runs without u, only A to Z, a to z, 0 to 9 and _ count as word characters. Replacement uses String.prototype.replace.
• Browser API or library: Native JavaScript RegExp and string methods, and a Web Worker for regex mode. No external library.
• Input limits: Regex mode updates live for input up to 200,000 characters, and each run is stopped after 2 seconds. Plain mode has no fixed limit. Match count is computed via matchAll.
• Output: Replaced text plus a numeric match count. Invalid regex patterns surface the engine's error message.
• Known limitations: Regex mode runs in a separate Web Worker, so a pattern with catastrophic backtracking is stopped after 2 seconds with a message instead of freezing the tab. Multi-file replacement is out of scope.

Frequently asked questions

Can I use regular expressions to find and replace?

Yes. Enable Regex mode and the find field accepts a full JavaScript regular expression pattern. Capture groups from your pattern can be referenced in the replacement field using $1, $2, etc.

Does the search distinguish uppercase and lowercase?

By default the search is case-insensitive. Enable the Case sensitive toggle to match exact case. This applies in both plain and regex modes.

How is the match count calculated?

The match count shows the total number of occurrences of the find pattern in the input text. It updates live as you type in either the find field or the input area.

Is my text sent to a server?

All text processing runs locally in your browser using JavaScript. No text or data is sent to our servers.