File Checksum Comparator
File Checksum Comparator calculates the chosen SHA digest for the first selected file and compares it with the entered value after trimming outer whitespace and ignoring letter case. It reports Match or No match and shows the calculated digest. It does not remove internal spaces, prefixes such as sha256:, or punctuation, and a match establishes byte equality with the supplied value—not origin or safety.
Runs locally — files stay on your deviceWhat does a checksum match prove?
It shows that the selected file produced the entered digest under the chosen algorithm.
Checksum verification needs two independent inputs
The local file supplies the bytes; a trusted external source supplies the expected digest. The value of the check depends on keeping those trust paths separate.
How it works
The first file is fully read, hashed with Web Crypto, converted to lowercase hex, and compared with the trimmed expected string case-insensitively.
Key concepts
Algorithm must match
A SHA-256 digest cannot match a SHA-512 value for the same file.
Formatting is strict
Only leading/trailing whitespace and hex letter case are normalized.
When to use it
- Validate a software download against a vendor checksum.
- Confirm a transferred archive retained identical bytes.
- Check a backup copy against a recorded digest.
When not to use it
- Do not use a checksum copied from an untrusted mirror.
- Do not interpret Match as a malware-free result.
- Do not paste formatted command output without isolating the digest.
Worked examples
Valid SHA-256
- Input
File plus its 64-character value- Expected output
Match
Algorithm and bytes agree.
Wrong algorithm
- Input
SHA-512 value while SHA-256 is selected- Expected output
No match
Digest lengths and values differ.
Changed download
- Input
One altered byte- Expected output
No match
The calculated fingerprint changes.
Common mistakes
Including a label
Text such as SHA256: remains part of the expected string. Correction: Paste only hexadecimal digits.
Selecting several files
Only the first is checked. Correction: Verify one file at a time.
Using an unauthenticated checksum
Equality does not establish publisher identity. Correction: Use HTTPS, a signed release, or another trusted channel.
Best practices
- Confirm the selected algorithm and expected length.
- Copy the digest from an authoritative source.
- Investigate every mismatch instead of overriding it.
Related operations and differences
File Hash Calculator
Choose File Hash Calculator when you need to calculate a local cryptographic file digest.; use File Checksum Comparator specifically for checksum.
Add Prefix to Filenames
Choose Add Prefix to Filenames when you need to add a prefix to selected filenames.; use File Checksum Comparator specifically for checksum.
Add Suffix to Filenames
Choose Add Suffix to Filenames when you need to add a suffix before every extension.; use File Checksum Comparator specifically for checksum.
Compare Two Files
Choose Compare Two Files when you need to compare two files securely by SHA-256.; use File Checksum Comparator specifically for checksum.
File Size Calculator
Choose File Size Calculator when you need to inspect exact and human-readable file sizes.; use File Checksum Comparator specifically for checksum.
File to Base64
Choose File to Base64 when you need to encode a local file as Base64.; use File Checksum Comparator specifically for checksum.
Limitations and privacy
- Only one selected file is compared.
- No checksum-file parser, digital-signature validation, malware scanning, or provenance check.
- The complete file is buffered in memory.
Processing happens in this browser. Selected file contents are not uploaded by this tool.
Downloads and copied results remain on this device; handle them according to their sensitivity.
Frequently asked questions
Are uppercase hex letters accepted?
Yes.
Are spaces inside the digest ignored?
No.
Does Match prove the file is safe?
No.
Is the calculated value displayed?
Yes.