File Hash and Checksum Calculator
Compute MD5, SHA-1, SHA-256 and SHA-512 for text or files in your browser and compare with a known hash.
- Runs in your browser, files never leave your device
- Free, open source, no account, no ads
- Works offline after the first visit
Hash a file or text
Drop files here or choose files
Any file of any size: an installer, ISO image, archive or document. Several at once is fine. Nothing is uploaded.
Paste a hash or a whole checksum line. Case, spaces, colons and a trailing file name are ignored.
Which one to use? Compare with whatever the publisher lists, usually SHA-256. MD5 and SHA-1 are broken for security (someone can craft two files with the same hash), but they are still fine for spotting accidental corruption from a bad download or copy.
How it works
- Drop a file or type text. Pick one or many files, or switch to the Text tab. The file is read on your device in small slices, so even a multi-gigabyte image works.
- Read the hashes. MD5, SHA-1, SHA-256, SHA-384 and SHA-512 appear together, each with a copy button, in hex or Base64.
- Paste the published hash. The Compare field checks it against every result and tells you which algorithm matched. Save all results as checksums.txt or a CSV.
Questions, answered
Are my files uploaded anywhere?
No. File Hash and Checksum Calculator runs entirely in your browser. Your files are read in slices on your device, hashed with JavaScript in a background worker, and never sent to a server. That matters most when you are checking a download you do not trust yet. You can disconnect from the internet and it keeps working.
Why does my text hash not match the one from the command line?
Almost always a newline. echo abc | sha256sum hashes "abc" plus a line break, which gives a different result from "abc" alone. Tick "Include a trailing newline" on the Text tab to match echo, or use printf on the command line. Text is hashed as UTF-8 bytes.
Are MD5 and SHA-1 still safe to use?
Not for security. Both are broken: an attacker can build two different files with the same MD5 or SHA-1. If a publisher lists SHA-256 or SHA-512, compare against that. MD5 and SHA-1 are still fine for catching accidental corruption, such as a truncated download or a bad copy to a USB stick.
Is it really free?
Yes. It is open source under the MIT license, with no account, no file size limit and no ads. If it saves you a paid subscription, you can say thanks on Ko-fi.
Does it work offline?
Yes. After your first visit the page is cached by a service worker, so it loads without a connection. You can also install it from your browser's menu as an app. Very large files on phones can run into memory limits, so a computer is the better choice for multi-gigabyte images.
Was this written by AI?
Yes. File Hash and Checksum Calculator was generated by Claude Code from a written specification inside an automated pipeline, with a test suite that runs in a real browser. The hash code checks itself against the standard "abc" test vectors and your browser's built-in WebCrypto every time it starts. The full source is on GitHub, so you can read every line before you trust it with your files.
Built by one person, given away for free
File Hash and Checksum Calculator is a free alternative to paid tools like Online MD5 and SHA hash generators and file checksum sites. If it earns a place in your bookmarks, a coffee keeps the updates coming.
☕ Support Or on Ko-fi