PDF Compressor — Compare Real File Size

How to use PDF Compressor with a clear next step.

Choose the PDFs you need to share, create a compact copy first, and compare the actual original and output sizes before downloading. If the normal compact copy is still too large, decide whether flatten-for-size is acceptable: it rebuilds pages as images and can reduce scan-heavy files, but it no longer preserves selectable text, links, or editable form fields. Keep the original until the downloaded copy opens and reads as intended.

A scan-heavy PDF and a text-based PDF can respond very differently to the same operation, so do not promise a percentage reduction before testing. Inspect fine text, decimal points, stamps and the last page rather than judging only the first-page thumbnail. If the output is still too large for a strict upload cap, use the target-size workflow and read its trade-offs instead of repeatedly compressing an already degraded copy. A file that becomes larger may have been efficiently encoded already; keep the smaller readable version. Encrypted or damaged inputs should be resolved with a valid source and the correct password, not renamed to bypass checks. Preserve the original and check whether text selection, links, fields or existing signatures matter to the recipient. A smaller byte count alone does not establish that the document is suitable for submission.

This local workflow processes the selected files in browser memory and reports the real output size instead of promising a fixed percentage reduction. A compact copy preserves compatible PDF objects where possible; optional flattening renders each visible page to a JPEG-backed PDF, which changes document behavior in exchange for a possible size reduction. Password-protected, damaged, very large, or complex PDFs can exceed browser capabilities.