A file checksum is a value calculated from the file’s bytes. Our tool uses SHA-256 and displays the result as 64 hexadecimal characters. It is useful when checking that a downloaded file matches a copy or an expected value supplied through a source you trust.
Compare the right things
Select a file and wait for the calculation to finish. If you have an expected SHA-256 value, paste it into the comparison field. Spaces around the value and uppercase hexadecimal letters are accepted. The tool reports whether the two complete values match.
Changing a file’s contents changes the input to the calculation. Renaming a file does not alter its contents, so renaming alone does not change its SHA-256 value. A ZIP archive and the files inside it are different byte sequences and have their own checksums.
Keep the expected value somewhere useful
For a small project archive, record the filename, file size, date of your calculation, and hash in a separate note. If you receive an expected value from another person or a software publisher, consider how you obtained that value. A hash copied from the same untrusted source as the file provides limited reassurance about its origin.
Know what it does not establish
A matching checksum is not a malware scan or proof of authorship. It compares bytes against an expected value. The tool processes the selected file in the browser and limits files to 50 MB to keep memory use modest.
Reference: MDN’s Web Crypto digest documentation.