Free AI Fact Checker
Find wrong facts in your text before you publish. Every claim is checked, explained and, if needed, corrected in one click. 500 words free, no sign-up.
Text to Fact-Check
What is an AI fact checker?
An AI fact checker finds the factual claims in a piece of text and checks whether they're true. HumanizerPRO's free AI fact checker breaks your text into separate claims, marks each one as true, false, partially true or unverifiable, explains why, and suggests a corrected sentence you can apply with one click.
It's built for drafts that mix facts with writing: essays, blog posts, reports and AI-generated text, which often contains confident mistakes. It uses the knowledge in GPT-4.1 rather than a live web search, so it's great for well-known facts and a first stop, not the last word, on breaking news.
- Free
- 500 words per check, no sign-up
- Paid plans
- Up to 5,000 words per check
- Results
- A verdict, explanation and suggested fix for every claim
- History
- Your last 30 checks, saved only in your browser
How the AI fact checker works
Click a step to see what happens to your text.
How to fact-check a text
A check takes a few seconds. Here's how to run one with HumanizerPRO.
- 1
Paste your text
Paste or type the text you want to check, or upload a file. Without an account you can check up to 500 words at a time.
- 2
Click Check Facts
Or press Ctrl+Enter. The checker finds every claim in a few seconds.
- 3
Review each verdict
Claims are highlighted in your text. Read the explanation for anything marked false, partially true or unverifiable.
- 4
Apply the fixes
Apply a suggested correction to one claim or all of them, then confirm anything important with a trusted source.
Does it catch mistakes? We tested it
In October 2026, the HumanizerPRO team gave the fact checker 20 short texts: 10 that each contained one planted mistake (such as "The Eiffel Tower was completed in 1899" or "Light from the Sun takes about 8 seconds to reach Earth") and 10 that were correct.
Planted mistakes caught, each with the right correction (1889, 8 minutes, and so on).
Correct texts confirmed as true. The other was marked partially true.
Wrong facts it marked as true.
The one correct text marked partially true said the Nile and the Amazon are the two longest rivers, a ranking experts still debate. See how AI fact checkers compare in our AI fact checker review.
What each verdict means
Every claim in your text gets one of four verdicts, with an explanation you can check.
True
The claim matches well-established facts.
Partially true
Part of the claim is right, or it needs context or a more precise wording.
False
The claim is wrong. A corrected sentence is suggested.
Unverifiable
There isn't enough trustworthy evidence to confirm it. This is often the case when a claim is very new or very specific.
What you get with this fact checker
Find wrong facts, understand why they're wrong and fix them, without leaving the page.
Claim-by-claim results
Each factual statement gets its own verdict, not just one score for the whole text.
Highlights in your text
Checked claims are marked in context and coloured by verdict, so you can see the problem spots at a glance.
One-click corrections
Apply a suggested fix to a single claim, or apply all fixes at once.
Plain explanations
Each verdict comes with a brief explanation, so you know what to look for and why.
Check history
Your last 30 checks are saved in your browser, with a search box. Nothing is saved to an account.
Free, no sign-up
Check up to 500 words at a time for free. Paid plans raise the limit to 5,000 words.
What an AI fact checker can't do
The checker uses GPT-4.1's knowledge, not a live search of the web. It's accurate on well-known facts such as dates, science, geography and history, but not on breaking news, recent statistics or very local details. Those often come back as unverifiable.
Treat it as a fast first pass. For anything important, such as health, legal or financial claims, confirm the fix with a trusted source before you publish. AI-written text is a common place for confident mistakes, so it's worth checking any draft from ChatGPT, or from our Human AI Writer, before it goes out.
Who uses this fact checker
Students
Check dates, names and figures in an essay before you submit it.
Writers and bloggers
Catch wrong numbers and outdated claims before a post goes live.
Anyone using AI
Check ChatGPT answers and AI drafts, which can state wrong facts with confidence.
Editors and journalists
Run a quick first pass on claims before the full fact-check.
More free tools
Frequently asked questions
Is this AI fact checker free?
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Yes. You can check up to 500 words at a time for free, with no account and no sign-up. Paid plans raise the limit to 5,000 words per check.
How accurate is the AI fact checker?
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In HumanizerPRO's October 2026 test, it caught all 10 planted mistakes in 20 short texts and suggested the right correction each time. It confirmed 9 of the 10 correct texts as true and didn't mark any wrong fact as true.
Does it search the web?
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No. Its knowledge comes from GPT-4.1, so it's most reliable on well-known facts. Very recent news and figures may come back as unverifiable, so always check those with a trusted source.
Can it fix wrong facts for me?
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Yes. Claims marked false or partially true come with a suggested corrected sentence. You can apply one fix, or apply all of them in one click.
Can I fact-check ChatGPT answers?
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Yes. Paste the answer into the checker and it will find each statement and flag anything that's wrong. AI tends to sound confident even when it's wrong, so it's always worth checking.
What does unverifiable mean?
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It means there isn't enough reliable information to confirm or reject the claim, for example very recent news, private details or exact figures without a source.
Is my text saved?
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Your check history is stored only in your own browser, and you can clear it whenever you want. HumanizerPRO doesn't save the text you check to an account.
What kinds of claims can it check?
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Most everyday facts: dates, numbers, names, places, science, health basics, history and technology. It's strongest on well-established facts and weakest on very recent events.