What it does
A hash is a short fingerprint of some data. Change one letter or one byte and the fingerprint changes completely. Download sites often print a SHA-256 or MD5 checksum next to a file so you can check that your copy arrived whole and was not swapped. This page works out five hashes at once for typed text or a file, and compares them with a checksum you paste.
Files are read on your device and never uploaded, so it also works with large or private files and with no internet once the page is open. To turn the raw bytes into text instead use the base64 converter; to read the parts of a login token try the JWT decoder.
How to use it
- Pick Text and type, or pick File and choose a file. The hashes appear below.
- To check a download, paste the published checksum in Expected hash.
- A green Match names the kind of hash that matched; otherwise you see No match.
- Use Copy next to any hash, or Clear to start again.
What each part does
- SHA-256: the usual choice today, 64 hex characters.
- SHA-512 and SHA-384: longer members of the same SHA-2 family.
- SHA-1: 40 characters; old and no longer safe against deliberate forgery.
- MD5: 32 characters; old and not secure, but still printed on many download pages.
- Expected hash: compared with all five, ignoring upper or lower case, spaces and a label such as “sha256:” in front.
Text is hashed as UTF-8 bytes, exactly as typed, so a space or line break at the end changes the result.
Worked example
The text abc is 3 bytes. Its SHA-256 is ba7816bf8f01cfea414140de5dae2223b00361a396177a9cb410ff61f20015ad and its MD5 is 900150983cd24fb0d6963f7d28e17f72, the test values given in FIPS 180 and RFC 1321. Pasting the SHA-256 in capitals still shows “Match: this is the SHA-256 hash”. A file holding just abc gives the same hashes.
FAQs
Why does my text not match? Check for a trailing space or line break, and that the other side hashed the same text encoding.
Can a hash be reversed? No. You can only hash a guess and compare.
Is this for storing passwords? No. Passwords need slow, salted schemes such as bcrypt or Argon2, not a plain hash.
Where the numbers come from
- FIPS 180-4, Secure Hash Standard (NIST) for SHA-1 and SHA-2, run by the browser's Web Crypto; RFC 1321 (IETF) for MD5, fibub's own small implementation.
Standard scientific values, such as constants, atomic weights and melting points, are facts found in every textbook; we name where ours were checked. If you are an author or publisher and want a value, a credit or a table changed or removed, tell us and we will act quickly.
Last updated 2026-11-10.