Compare Two Files
Compare Two Files requires exactly two selections, calculates SHA-256 over every byte of both in parallel, and reports identical when the hexadecimal digests match. Different filenames, timestamps, MIME labels, and other external metadata do not matter. A match is strong evidence of byte equality, but the page does not show hashes on a match or perform semantic, visual, textual, or authenticity comparison.
Runs locally — files stay on your deviceWhat does “identical” mean here?
Both selected files produced the same SHA-256 digest for their complete bytes.
Byte comparison differs from meaningful-content comparison
Two documents can look alike while their bytes differ, or share identical bytes under different filenames. Hash comparison answers only the byte-identity question.
How it works
Exactly two files are fully buffered and hashed with SHA-256. Equal hex digests return an identical message; a mismatch displays both names and hashes.
Key concepts
External names are ignored
Only file bytes enter SHA-256.
Semantic equality is broader
Equivalent text with different line endings hashes differently.
When to use it
- Check whether a copy changed during transfer.
- Identify byte-identical duplicates with different names.
- Confirm an exported artifact matches a reference file.
When not to use it
- Do not compare visual similarity of images or PDFs.
- Do not infer which file is newer or correct.
- Do not use it as signature or malware verification.
Worked examples
Renamed copy
- Input
a.pdf and copy.pdf with same bytes- Expected output
Files are identical
Names are outside the digest.
Line-ending change
- Input
LF text and CRLF text- Expected output
Files differ
Their bytes differ.
One selection
- Input
a.bin only- Expected output
Input error
Exactly two files are required.
Common mistakes
Calling visual matches identical
Rendering similarity is not tested. Correction: Use a format-aware visual comparison.
Selecting more than two
The page rejects the set. Correction: Choose one pair.
Assuming a matching pair is trustworthy
Both copies could be malicious. Correction: Verify provenance separately.
Best practices
- Select the intended pair and note their roles.
- Use semantic diff tools when byte differences are expected.
- Retain a trusted reference hash when provenance matters.
Related operations and differences
Add Prefix to Filenames
Choose Add Prefix to Filenames when you need to add a prefix to selected filenames.; use Compare Two Files specifically for compare.
Add Suffix to Filenames
Choose Add Suffix to Filenames when you need to add a suffix before every extension.; use Compare Two Files specifically for compare.
File Checksum Comparator
Choose File Checksum Comparator when you need to compare a file digest with an expected checksum.; use Compare Two Files specifically for compare.
File Hash Calculator
Choose File Hash Calculator when you need to calculate a local cryptographic file digest.; use Compare Two Files specifically for compare.
File Size Calculator
Choose File Size Calculator when you need to inspect exact and human-readable file sizes.; use Compare Two Files specifically for compare.
File to Base64
Choose File to Base64 when you need to encode a local file as Base64.; use Compare Two Files specifically for compare.
Limitations and privacy
- Exactly two files, both fully buffered.
- No partial, folder, visual, text, metadata, signature, or malware comparison.
- Digest values are displayed only when files differ.
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
Can names differ?
Yes.
Are timestamps compared?
No.
Which algorithm is used?
SHA-256.
Can matching hashes prove authorship?
No.