urlkit[ CHECK / #256 ]
File checksum
Calculate a local file’s SHA-256 and compare an expected checksum.
02 / Your result
Your result will appear here.
Start with your own input or try an example.
What it does
Check whether a downloaded file agrees with a checksum from its publisher, or make a fingerprint to compare copies later. Select a local file up to 20 MiB and optionally paste an expected SHA-256. The tool hashes the exact bytes in your browser and reports whether the values match; it does not upload the file.
Useful when
- Compare a downloaded archive with its publisher’s SHA-256.
- Check whether two small file copies have the same fingerprint.
- Record a checksum before sharing a document or configuration file.
How to use it
- Choose a local file up to 20 MiB, or try the small built-in example.
- Optionally paste a trusted SHA-256 value, then calculate the checksum.
- Review the match result and copy or download the hexadecimal checksum.
A few useful details
Does a matching checksum mean a file is safe?
No. It means the calculated digest equals the value you supplied. A malicious file can have a matching checksum too. Obtain the expected value from a source you trust; this tool is not a malware scan or a signature verifier.
Why is there a 20 MiB limit?
The browser’s Web Crypto digest API takes the complete file in memory. The limit bounds memory use. Use an appropriate local command-line checksum tool for larger files.
Does renaming the file change its checksum?
No. Only the file bytes are hashed; its name and metadata are not included. Editing content, changing a text file’s line endings, or recompressing an archive can change its checksum.
What is inside the .sha256 download?
The file contains only the 64-character hexadecimal digest and a newline. It does not include a filename and is not a multi-file sha256sum manifest.