Find and Replace Text
Many find-and-replace rules at once, with regex, case options and highlighted changes.
Nothing leaves your device.
Find and replace rules run from top to bottom
With Regex on, the Find box is a JavaScript regular expression: ^ and $ match at each line, and in the
replacement $1 or $<name> insert groups, $& the whole match, \n a new line and \t a tab.
Try patterns in the Regex Tester.
Result
About the Find and Replace Text
Paste your text (or open a text file), add one or more rules, and every match is replaced at once. Rules run from top to bottom, so you can chain them: rename a product, then reformat dates, then fix a spelling. Each rule shows how many matches it found, and the result highlights everything that changed.
A rule can be plain text — symbols such as $, . or ( are found literally — or a JavaScript regular expression with groups ($1, $<name>) in the replacement. Match case, Whole words and Preserve case (CAT → DOG, Cat → Dog) work in both modes. Long rule lists can be imported from a CSV file with find,replace on each row.
How to use it
- Paste the text, or use Open file for a .txt, .csv, .md or code file.
- Type what to Find and what to Replace with. The count next to the rule shows how many matches it found.
- Tick Match case, Whole words, Preserve case or Regex as needed. Add more rules with Add rule; use the arrows to change their order.
- Check the highlighted result, then Copy or Download it. Use as input makes the result the new text for another round.
- Keep a rule list for later with Export CSV, and load it again with Import CSV.
Examples
Find: (\d{4})-(\d{2})-(\d{2}) · Replace: $3/$2/$1 · Regex
Shipped on 2026-09-28.Shipped on 28/09/2026.
Find: colour · Replace: color · Whole words, Preserve case Colour, colour, COLOUR and colourful
Color, color, COLOR and colourful
“colourful” is left alone because Whole words only matches the complete word.
Find: ,\s* · Replace: \n · Regex apples, pears,plums
apples pears plums
Common uses
- Renaming a product, person or term throughout a document or a batch of copy.
- Cleaning exported data: reformatting dates, phone numbers or separators with regular expressions.
- Applying a glossary or a style guide (US → UK spelling, brand names) from a CSV list of replacements.
- Editing code or configuration text when you do not have an editor with multi-rule replace.
Rule options
- Match case: "cat" does not match "Cat" or "CAT". Off by default.
- Whole words: only complete words match, so "cat" does not match inside "category". Letters and digits in every script count as word characters.
- Preserve case: the replacement follows the case of each match — ALL CAPS, Capitalised or lower case. Mixed case such as "iPhone" keeps the replacement as you typed it.
- Regex: the Find box is a JavaScript regular expression.
^and$match at the start and end of every line, and.does not match a line break.
Replacement patterns (Regex on)
$1…$99— a numbered group;$<name>— a named group such as(?<year>\d{4})$&— the whole match; `$`and$'— the text before and after it;$$` — a dollar sign\n— a new line,\t— a tab,\\— a backslash
With Regex off, the replacement is used exactly as typed, including any $ signs.
CSV rule files
Each row is one rule: find,replace. Optional columns after them switch options on with yes or no: regex, match case, whole word, preserve case. A header row with these names may come first, in any order, and semicolon- or tab-separated files work too. Put a cell in double quotes if it contains a comma, and double any quote inside it.
Example:
find,replace,whole wordcolour,color,yes"Mumbai, India","Mumbai, Maharashtra",no
Limitations
- Rules run one after another on the result of the previous rule, so a later rule can change text that an earlier rule inserted. Change the order if that is not what you want.
- A regular expression that takes longer than 4 seconds (usually one with nested repeats such as
(a+)+) is stopped, and the text is left as it was. - Text up to 5 million characters can be processed; the highlighted view shows the first 200,000 characters.
- Your rules are not saved when you leave the page. Use Export CSV to keep them.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
How do I replace several different words at once?
Add a rule for each word with Add rule, or import them all from a CSV file with one find,replace pair per line. All the rules run in order on the same text.
How do I replace line breaks?
Tick Regex and find \n (or \r?\n for files from Windows). In the replacement, \n inserts a line break, so you can also split text onto separate lines.
Why does my regex find nothing?
Check that Regex is ticked, and that Match case is off if the case may differ. Characters such as ., ?, ( and [ have special meanings in a regex; put a backslash before them to find them literally. You can test a pattern step by step in the Regex Tester.
What does Preserve case do?
It copies the case of each match to its replacement: replacing "cat" with "dog" turns "CAT" into "DOG", "Cat" into "Dog" and "cat" into "dog".
Is my text uploaded?
No. All rules run in your browser, and nothing you paste or open is sent anywhere.