Find and Replace Online Across Whole Documents

How to Use Find and Replace Online

1. Paste your document into the box — or press Load sample to work on the example paragraph about cats.
2. Type the Find text and the Replace with text — the fields arrive preset with cat and dog so you can watch it work.
3. Leave the options off for a friendly case-insensitive pass, or tick Case sensitive and Whole words only to narrow the matches.
4. Tick Use regular expression only if your Find text is a pattern rather than literal words.
5. Read the result and the note — it reports the exact number of replacements made.

About this tool

Every writer and developer knows the pain: a name is misspelt forty times, a product is renamed, a date format changes everywhere at once. Find and Replace fixes the whole document in one pass and reports exactly how many replacements it made, so you can verify nothing was missed. The defaults are friendly. Matching ignores case, and it is substring-based, so “cat” also matches inside “cats” and “catalogue”. Tick Case sensitive when “Cat” and “cat” are genuinely different targets, and Whole words only when a match must stand alone as a complete word. Every run ends with the exact report — so a surprising count tells you to look closer before you keep the result. Regular-expression mode turns it into a precision instrument for finding: \d hunts digits, \b marks word boundaries, and (a|b) offers alternatives — reformat-hunting across an entire file in one pass. One honest limit to know: the replacement is inserted literally, so capture-group references like $1 are typed into the result as-is rather than expanded. Use regex here for finding and counting patterns, and keep replacements as simple text. Two more behaviours are worth knowing: an empty Find box changes nothing, rather than matching everywhere at once; and an invalid pattern earns you a plain explanation of what is wrong with it, not a silent failure. The whole pass runs in your browser, safe for drafts, manuscripts and internal documents. New to patterns? MDN's regular expressions guide is the reference this tool's regex mode follows.

Worked example

Here is the sample paragraph that comes with the tool, with the preset Find (cat) and Replace with (dog) at the default settings: You paste

The cat sat. The Cat ate. A cat, another cat — cats everywhere, but only some are capitalised.

You get

The dog sat. The dog ate. A dog, another dog — dogs everywhere, but only some are capitalised.

The note reads “5 replacements made.” Count them: four standalone cats — including “Cat”, matched because case is ignored, and replaced with the replacement exactly as typed, so it lands lowercase — plus the cat inside “cats”, which became “dogs”. Whole words only would have stopped that fifth one.

Features

• Whole-document passes with an exact replacement count reported after every run.
• Case control: friendly case-insensitive matching by default, case-sensitive when it matters.
• Whole-word mode, so “cat” no longer matches inside “cats” or “catalogue”.
• Regular-expression finding for patterns — digits, boundaries, alternatives — with plain errors for invalid patterns.
• Literal replacements inserted exactly as typed; an empty replacement deletes every match.
• Private by design: the pass runs in your browser — safe for drafts and internal documents.