unmark

Remove the AI watermark from any text

SynthID and other statistical watermarks hide a detectable fingerprint in AI text. Unmark rewrites it away while keeping your meaning.

SynthID & statistical marksInvisible charactersFree & private
Paste AI text0 chars
Watermark-free text0 chars
Your watermark-free text appears here.
Strength
Humanise — natural rewrite, same length & meaning.
Paste AI text, then remove its watermark.
▸Hidden-character optionscore invisibles, tags & private-use are always removed
Three steps

How to remove an AI watermark

No account, no setup — paste, remove, copy. Works with text from ChatGPT, Claude, Gemini and any other AI. New here? Read the full guide to removing AI watermarks.

01

Paste your AI text

Drop in text from ChatGPT, Claude, Gemini, Copilot or anywhere else. Unmark scans it for hidden characters instantly, in your browser.

02

Remove the watermark

Pick a strength and hit Remove watermark. Unmark rewrites the wording to break the SynthID / statistical watermark, and strips every invisible character in the same step.

03

Copy clean text

Copy or download watermark-free text that reads the same to a human, minus the machine fingerprint.

Two watermarks, one tool

What Unmark removes

Token-level fingerprint

Statistical & SynthID watermarks

Used by Google’s SynthID and now Claude, these hide in the model’s word choices and survive light editing. Unmark rewrites your text to scramble the pattern while the meaning stays intact.

Invisible fingerprint

Hidden-character watermarks

Zero-width spaces, bidi controls, tag characters and look-alike glyphs woven between letters — revealed and stripped instantly, in your browser.

Background

Understanding AI text watermarks

As AI writing tools became mainstream, providers began embedding watermarks in their output so it can later be identified as machine-generated. These marks come in two very different forms, and removing one does nothing about the other.

Statistical watermarks (SynthID)

A statistical watermark such as Google’s SynthID-Text subtly biases which words and tokens the model picks, creating a pattern that a matching detector can measure across a passage. Because it lives in the word choices themselves — not in any visible mark — trimming a sentence or swapping a few words rarely clears it. The dependable way to remove it is to rewrite the text enough that the token sequence no longer matches, which is exactly what Unmark does while preserving your meaning.

This went mainstream in 2026: alongside Google’s SynthID, Anthropic announced that future Claude models will watermark their output with a SynthID-style statistical method — applied by default, with no opt-out, to help comply with the EU AI Act. Anthropic notes that light editing may leave the mark intact, but a complete rewrite removes it — which is exactly the rewrite Unmark performs.

Invisible-character watermarks

The second kind hides invisible Unicode between the letters: zero-width spaces and joiners, byte-order marks, bidirectional controls, tag characters and look-alike glyphs. They render as nothing on screen but survive copy-paste, so they can fingerprint or track text. Unmark detects and strips them in your browser — while carefully preserving load-bearing marks such as emoji sequences — so the readable text is untouched but the hidden payload is gone.

Questions

Frequently asked questions

What is an AI text watermark?+
It's a hidden signal that flags text as AI-generated. There are two families: statistical watermarks (like Google's SynthID) that bias the model's word choices into a pattern a detector can measure, and hidden-character watermarks that weave invisible Unicode between the letters. Unmark removes both.
What is SynthID, and can Unmark remove it?+
SynthID-Text is Google's watermark that nudges the model's token choices into a statistical pattern — it stays even after you edit a few words. Unmark rewrites the whole text so that pattern is scrambled while your meaning stays intact, which is the only reliable way to strip a statistical watermark.
Does Claude watermark its text, and can Unmark remove it?+
Anthropic has announced that future Claude models will watermark their text with a SynthID-style statistical method, applied by default with no opt-out to help comply with the EU AI Act. Light edits won't clear it, but a full rewrite will — which is exactly what Unmark does, while keeping your meaning.
How do I remove an AI watermark from text?+
Paste the text, choose a rewrite strength, and click Remove watermark. Unmark rewrites the wording to disrupt the statistical/SynthID watermark and strips invisible characters at the same time, then you copy the clean result. It's free and runs in your browser.
Can Unmark make AI text undetectable?+
Rewriting substantially degrades statistical watermarks and AI-detector signals, and stronger settings degrade them more. But no tool can promise a text is permanently undetectable against every future detector — treat Unmark as best-effort de-watermarking, and always re-read the result.
Does it remove invisible or zero-width characters?+
Yes. Unmark scans in your browser for zero-width spaces, joiners, byte-order marks, bidirectional controls, the Unicode tag block, exotic spaces and look-alike glyphs, and strips them — while preserving load-bearing marks like emoji sequences. This runs instantly and is applied to every rewrite.
Which AI tools does it work with?+
Any of them. Unmark works on plain text, so it removes watermarks from ChatGPT, Claude, Gemini, Copilot, Llama and any other AI output — just paste the text in.
Is Unmark free?+
Yes, Unmark is free to use. The hidden-character scan runs entirely in your browser, and the rewrite is available at no cost.
Is my text private?+
The hidden-character scan runs 100% locally in your browser. The rewrite is processed server-side and streamed back — your text is not stored.
Will rewriting change my meaning or formatting?+
The rewrite preserves your meaning, keeps the original language, and keeps roughly the same length. It's instructed to preserve facts, numbers and names; heavier strengths reword more, so re-read the result to confirm it kept your intent.
Does removing the invisible characters change how the text reads?+
No. Every hidden character Unmark strips is invisible or a look-alike of a standard character, so the visible, readable text is identical — just without the hidden payload.