Free SHA-256 Hash Checker

A SHA-256 hash is a file’s fingerprint: a 64-character code that changes completely if even one byte of the file changes. It is how software publishers let you check a download, how IT teams confirm two copies match, and how evidence workflows show a file hasn’t been altered. Below is a free SHA-256 file hash checker that runs entirely in your browser, so your file is never uploaded. After it, you’ll find how to verify a download checksum, how to compare two files, and what a hash can and can’t prove.

Check a file’s SHA-256 hash now

Choose or drop one or more files to see their SHA-256 hashes, paste a published checksum to verify a download, or compare two files to see whether they are identical. The file is read and hashed on your device. Nothing is sent to TimeBinder or anyone else, and the tool keeps working offline once the page has loaded.

What is a SHA-256 hash?

SHA-256 is a cryptographic hash function from the SHA-2 family, published by the US National Institute of Standards and Technology in FIPS 180-4, the Secure Hash Standard. It takes a file of any size, from an empty text file to a 50 GB video, and produces a fixed 256-bit value, usually written as 64 hexadecimal characters (0 to 9 and a to f).

Four properties make it useful:

• Deterministic. The same file always gives the same hash, on any computer and with any correct tool. You can check the result above against your own computer’s built-in commands.
• Sensitive to every change. Change a single byte and the hash changes completely, not just slightly. There is no “nearly the same” hash.
• One way. You can’t work backwards from a hash to the file, so publishing or sharing a hash doesn’t reveal the file’s contents.
• Collision resistant. No one has ever found two different files with the same SHA-256 hash. That is why a matching hash is treated as strong evidence that two files are identical.

A hash only covers the file’s contents. The file name, folder and “date modified” aren’t part of it, so renaming or copying a file doesn’t change its hash.

How to verify a download checksum

Many publishers list a SHA-256 checksum next to their downloads, especially for operating system images, installers, firmware and datasets. Checking it confirms that the file you received is exactly the file they published, not a truncated, corrupted or swapped copy.

1. Copy the SHA-256 checksum from the publisher’s official site. Make sure the page is the real one, served over HTTPS.
2. In the checker above, open Verify a checksum and paste the hash. Capital or lower-case letters and extra spaces don’t matter, and you can paste a whole line such as <hash> setup.exe.
3. Choose the file you downloaded. You’ll see Match or No match, with both hashes shown so you can compare them yourself.

The checker also recognises SHA-1, SHA-384 and SHA-512 checksums by their length. If the publisher only offers MD5, ask for a SHA-256 hash instead: MD5 is no longer considered secure against deliberate tampering.

If you get No match, don’t open or install the file. Download it again from the official source. If it still doesn’t match, the file may have been changed, or you may be comparing it with the checksum for a different version.

A checksum is only as trustworthy as the place you got it from. If an attacker can replace the download, they may be able to replace the checksum on the same page too. For high-stakes software, publishers often also provide a digital signature, which proves who published the checksum.

You can also check a hash without a browser, using tools already on your computer:

• Windows (PowerShell): Get-FileHash .\file.iso. SHA-256 is the default, according to Microsoft’s Get-FileHash documentation. In Command Prompt, use certutil -hashfile file.iso SHA256.
• macOS: shasum -a 256 file.iso in Terminal.
• Linux: sha256sum file.iso.

All of these give the same 64 characters as the checker above for the same file.

How to compare two files

File names, sizes and dates can mislead. Two files called contract-final.pdf can be different, and two files with different names can be identical. Comparing their hashes settles it: open Compare two files, choose file A and file B, and the checker tells you whether they are identical byte for byte.

This is useful when you need to:

• check that a backup or a copy on a USB drive matches the original;
• confirm that the version a client signed is the version you sent;
• see whether a “final” design, audio mix or document was changed after it was shared;
• remove duplicates from a folder of photos or recordings.

A hash tells you whether two files differ, not where. If they differ, a document comparison or diff tool will show what changed.

Why a no-upload hash checker matters

Many online hash tools ask you to upload your file to their server. That means sending a copy of a contract, medical record, unreleased track or confidential design to a third party just to get a 64-character code, and trusting them to delete it afterwards.

You don’t need to. Modern browsers can calculate SHA-256 themselves, so this checker reads the file on your device and does the maths locally. You can test this by loading the page, switching off your internet connection and hashing a file: it still works.

TimeBinder works the same way. When you timestamp files, they are hashed locally in your browser and only the fingerprints leave your device. The files themselves are never uploaded or stored.

What a hash can and can’t prove

A SHA-256 hash is very good at one thing: showing whether a file is exactly the same as another file, or as a hash recorded earlier. If you recorded a file’s hash last year and it still matches today, the file hasn’t changed.

But a hash on its own can’t show:

• When the file existed. Anyone can calculate a hash today. A hash written in your notes, or a file’s “date created”, can be edited or backdated. Nothing in the hash itself shows when it was made.
• Who created the file. A hash describes the contents, not the author.
• Whether the contents are true. A faked photo has a perfectly valid hash. A hash shows a file hasn’t changed since it was hashed, not that it was genuine to begin with.

That last point matters more now that AI can produce convincing fake images, audio and documents. If you have a reliable record of a file’s hash from before a dispute arose, you can show the file you have today is the same one. We explain this in more detail in how to prove your files are genuine when deepfakes are everywhere.

How to show when a file existed

To prove when, the hash needs to be recorded somewhere that you can’t quietly edit later and that anyone can check. That is what blockchain timestamping does.

TimeBinder anchors your files’ SHA-256 fingerprints to the Bitcoin blockchain, where each block carries a time and can’t be changed afterwards without redoing the work of every block since. You get a Proof of Time Certificate that shows the file existed in that exact form by a certain time and hasn’t changed since. Later, anyone you share it with can re-hash the file and check it against the record. See blockchain file verification for how the check works.

It is useful wherever timing may be questioned later: contract drafts, design files, research data, site photos, or a song demo and its signed split sheet. Our free split sheet generator creates the split sheet for that last one.

AI can rewrite files. It can’t rewrite time. The Free plan includes 1 Pooled TimeBind a month, each TimeBind can hold up to 10 files, and your files never leave your device.

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