File Checksum & Verify
What a file checksum is
A checksum is a short fingerprint of a file: run the file through a hash function like SHA-256 and you get a fixed-length string that changes completely if even a single byte of the file changes. Publishers post these values next to a download so you can confirm the file you received is exactly the one they released.
How to verify a download
Drop your file in, and the tool computes its SHA-256, MD5, SHA-1, and SHA-512 checksums. Paste the value from the download page into the verify box: a “Match” confirms the file is identical to the published one — it was not corrupted in transit or tampered with. A “No match” means the file differs, or the source used a different algorithm.
Private by design
Everything is computed locally in your browser — the SHA family via the built-in Web Crypto API and MD5 via a bundled implementation — so the file never leaves your device, and you can check sensitive documents or large installers without uploading them anywhere. MD5 and SHA-1 are provided to match older download pages; they catch accidental corruption but are not secure against tampering, so prefer SHA-256 when it is offered.
Frequently asked questions
Is my file uploaded anywhere?
No. The checksum is computed locally with your browser’s built-in Web Crypto API, so the file never leaves your device — you can verify sensitive files privately.
Which checksums does it produce?
SHA-256, MD5, SHA-1, and SHA-512. SHA-256 is the modern standard most download pages publish and the one to prefer. MD5 and SHA-1 are included so you can still match older pages that only list those — note MD5 detects accidental corruption but is not secure against deliberate tampering.
How do I verify a download?
Drop the file in, then paste the checksum from the source into the verify box. A green “Match” means the file is identical to what the publisher released; “No match” means it differs or a different algorithm was used.
Is there a file-size limit?
Files up to 1 GB are supported. Because the whole file is read into memory to hash it in your browser, very large files are capped to keep the page stable.