Last updated: 11 November 2026

Free tool: runs in your browser

Was this file changed?Free file comparison checker

TimeBinder adds a layer of protection against AI and human fraud and disputes. Drop two files to see in seconds whether they are exactly the same.

The file stays on your device. Your browser makes a SHA-256 fingerprint of each file and compares them.

Compare two files

Choose or drop a file in each box. The verdict appears as soon as both fingerprints are made.

The file stays on your device. Your browser makes the fingerprint and does the comparison.

File A: drop it here or choose a fileFor example, the original or the copy you were sent first. File B: drop it here or choose a fileFor example, the copy you want to check.

Fingerprint type: SHA-256, made with your browser’s built-in Web Crypto, or a built-in routine for very large files. Names and dates are shown for reference only; the result depends on the contents of the files.

What is a TimeBind?

A TimeBind is a dated, checkable record that an exact file existed no later than a recorded time and still matches. The SHA-256 fingerprint is made in your browser, the file is never uploaded, and the fingerprint is anchored to Bitcoin. It does not show who made the file or that its contents are true.

Was this file changed? The short answer

A file comparison checker tells you whether two files are exactly the same, byte for byte. It makes a SHA-256 fingerprint of each file and compares them: matching fingerprints mean identical files, and fingerprints that differ, even by one character, mean the files are different.

It cannot tell you which file is older, who changed it, or whether AI was involved. To show which version existed first, you need a dated record made at the time, as explained below.

How to read the result

The checker looks only at the contents of the files. A rename or a new file date does not change the result.

What each result means and what to do next
Result	What it means	What to do next
Match	The contents are identical. Names, dates and folders can still differ.	Keep one copy. If the date matters, make a TimeBind of the one you will rely on.
No match, sizes differ	The contents are different. The files are not the same version.	Work out which version you need and keep both unchanged. Use your program’s compare feature to see what changed.
No match, same size	The contents differ but have the same length, for example one digit or letter swapped.	Treat them as two versions. Do not overwrite either.
No match, but they look the same	Something not visible changed: a re-save, a different export, compression or metadata.	Ask for the original file rather than a re-saved copy, then compare again.

Which version came first? A comparison cannot say

A match or a mismatch shows whether two files are the same. It does not show when either file was made, because dates on a computer can be changed in seconds. To show which version existed first, you need a record of the exact file made at the time, held by someone other than the person disputing it.

Settle the exact version. Choose the file you will rely on and stop editing it. Work from a copy if you need to keep changing things.
Make a TimeBind before you send, sign or share it. Your browser makes the fingerprint and the file stays on your device. TimeBinder records the fingerprint with a time on the Bitcoin blockchain.
Keep the file and the Proof of Time Certificate together. Do not open and re-save the original.
Check later. If someone shows you a file, compare it with yours here, or check it against the certificate. A file that still matches existed no later than the recorded time. One that does not match is a different file.

Make a TimeBind: first one free →

First Pooled TimeBind free, no card, then from US$5. An ASAP TimeBind is US$15.

What a TimeBind shows, and what it does not. It shows that an exact file existed no later than a recorded time and that a copy shown later still matches its fingerprint. It does not show who made the file, who owns it, that its contents are true, or whether AI was used to make or edit it. This is general information, not legal advice.

File comparison checker: FAQ

How do I check whether two files are identical?

Drop one file in each box above. Your browser makes a SHA-256 fingerprint of each file and compares them. If the fingerprints match, the files are identical, byte for byte. If they differ, the files are different, even if they look the same on screen.

Does this tool upload my files?

The file stays on your device. Your browser reads each file and makes the SHA-256 fingerprint locally, then compares the two fingerprints. The page itself loads from timebinder.io like any web page, but the files you choose stay on your device.

Why do two files that look the same say No match?

The comparison is of the exact bytes, not how the file looks. Opening and re-saving a document, exporting a PDF again, compressing an image, or sending a photo through a messaging app can change the bytes without any visible edit. A mismatch tells you the files are not identical. It does not tell you who changed them or why.

Can this tell me which file is older, or who edited it?

No. A fingerprint comparison shows whether two files are the same or different. It says nothing about which was made first, who changed one, or when. To show an exact file existed no later than a recorded time, you need a dated record made at the time, such as a TimeBind.

Can it show whether a file was edited with AI?

No. It only compares two files with each other. If you have the original and a copy, a mismatch shows the copy is different from the original. It cannot detect AI, and a match does not show a file is genuine, only that it is the same as the other file.

How do I prove which version of a file came first?

Make a TimeBind of the version before you send, sign or share it. Your browser makes the fingerprint and the file stays on your device. TimeBinder records the fingerprint with a time on the Bitcoin blockchain and gives you a Proof of Time Certificate. Later, a file that still matches that fingerprint existed no later than the recorded time. Your first Pooled TimeBind is free with no card, then from US$5.

Is there a file size limit?

There is no fixed limit set by this page. Files up to 256 MB are read in one go; larger files are read in chunks, which is slower, and very large files depend on your browser and device memory. If a file cannot be read, try a smaller one or a different browser.

Related guides and tools

Your file’s fingerprint, anchored to a global network secured by real electricity and cryptography.

Editing a file—including with AI—changes its fingerprint, not its existing network record.

How this works

Your file’s SHA-256 fingerprint, a short code worked out from its exact contents, is made in your browser, and the file itself stays on your device. A cryptographic commitment to that fingerprint, which may be combined with others, is then anchored in a block on the Bitcoin blockchain. Bitcoin is secured by proof of work: computers around the world spend real electricity to add each block, and changing an earlier block would mean redoing that work faster than the rest of the network. Until that block is confirmed, your proof is pending. Once the Bitcoin anchoring is confirmed, you can verify the proof against that recorded commitment. The confirmed record can then be checked; Pooled TimeBinds are checked through TimeBinder, while ASAP TimeBinds can also be checked independently. If you check the file later and its fingerprint still matches, that shows the file existed no later than the recorded time. The record doesn’t show who made the file, whether AI was used, or that its contents are true.

Your filestays on your device
FingerprintSHA-256
Network timestampon Bitcoin

Date the version you rely on

Add a layer of protection against AI and human fraud and disputes: a dated, checkable record of the exact file you hold.

Open the app and sign in with email or Google.
Add your files. They stay on your computer.
Seal them and download your Proof of Time certificates.

Open TimeBinder →

First Pooled TimeBind free, no card, then from US$5. See pricing.