Verify a downloaded file

Make sure the program or file you downloaded is exactly the official one — not corrupted, not swapped for a version with malware. Drop the file, paste the official code and get a clear yes or no.

Your files stay on your deviceFree, no sign-up

Before you use it

Works well for

  • Installers, ISO images and firmware
  • Checking that a backup copy is identical
  • Large files of any size

Not the right tool for

  • Proving who made a file (that needs a digital signature)
  • Detecting malware by itself — it only compares with the official code

What a checksum is

A checksum (or hash) is a fingerprint of a file: a long code calculated from every byte. Change a single byte and the code changes completely. Software publishers list the SHA-256 code next to their downloads so you can confirm you got exactly their file.

Why check it

  • Fake download sites and ads that look like the real one can serve installers with malware.
  • Hacked mirrors have distributed tampered versions of real software.
  • Broken downloads can make an install or a firmware update fail halfway.

How to use it

  1. Find the checksum on the official site (not on the page that offered the download).
  2. Drop your file here and paste that code.
  3. Green means identical. Red means don't open the file.

Which algorithm?

Prefer SHA-256 or SHA-512. MD5 and SHA-1 still catch download errors but can be deliberately forged, so they don't prove a file wasn't tampered with.

Frequently asked questions

Is my file uploaded?

No. It's read in small pieces inside your browser, so even multi-gigabyte files work without leaving your device.

The codes don't match. What now?

Delete the file and download it again from the official site. If it still doesn't match, don't install it.

Where do I find the official checksum?

On the publisher's download page, often next to the file or in a “checksums” / “SHA256SUMS” file.