Check it against the original you already trust

Drop the file you trust and the file you are verifying. Both are parsed in memory and never saved.

Original the file you already trust

Drop a PDF, or

Max 10 MB · processed in memory, never stored

Candidate the file being verified

Drop a PDF, or

Max 10 MB · processed in memory, never stored

No two files handy? Try the sample pair:

Two fictional utility statements: the original, and a copy that gained a second revision lowering the total. Its report is precomputed, so it needs no account and costs no quota. Download the original · download the copy.

Only identical bytes are a proof: every rung below it narrows what you are entitled to say.
WHAT THE COMPARISON FINDS WHAT YOU MAY SAY FROM IT Identical bytes both files hash to the same SHA-256 It is the same file. the only result that is a proof Revision ancestry the candidate contains the original byte for byte, with later revisions appended after it Exactly what was appended, and whether it touched page content. signing and form-filling look like this too Structure only at least one file was re-saved whole; ancestry is reset Whether and where they differ. not what changed on the page No rung on this ladder asserts that the rendered pages look the same.

Which rung a comparison reaches is decided by the two files, not by a setting you choose. How each one is computed.

Bring the original, not a copy of it. A file that was re-saved on its way to you (re-exported, or printed to PDF) lands on the bottom rung, and the strongest thing a comparison can say is gone before it starts. The copy still sitting in your own system is the one worth uploading.