Big PDFs usually owe their size to images — scans and photos embedded at far higher resolution than anyone will view them. This tool shrinks them the honest way: it re-renders each page as a JPEG at the resolution you choose and rebuilds the PDF, then shows you the true before-and-after sizes. No inflated “up to 90% smaller” promises — the numbers on your file are the numbers you get.
Choosing a level
150 DPI (Recommended) is screen-sharp and prints acceptably — the right default for email and sharing. 200 DPI keeps print quality close to the original with modest savings. 100 DPI suits documents that will only be read on screens. 72 DPI is a last resort for squeezing under a strict upload limit; text gets soft.
What this method can and cannot do
Because pages are re-rendered, they become images inside the new PDF: text is no longer selectable or searchable, and vector graphics are flattened. PDFs that are already efficiently compressed — typical text documents saved from Word — may not shrink at all, and can grow; the tool tells you plainly when that happens instead of pretending otherwise. For those files the better fix is usually removing pages (Split tool) rather than recompressing.
Private by design
Like every CalcViso file tool, this one runs entirely in your browser. The file you choose is read by this page, processed on your device, and offered back as a download — it is never uploaded to a server, never stored, and never seen by anyone else. Close the tab and it is gone from memory.
Worked example
Use the sample: it is a 2-page PDF with a full-page photo embedded on each page. Results vary a lot by file — in testing, this photo-heavy sample came back about 18% smaller at Recommended. Scans and photo PDFs shrink the most; a text-heavy PDF is already compact and can even come back larger. Either way the results table shows the exact before-and-after sizes for your file, so you can watch a real, measured result happen.
How to use this tool
- Drop your PDF onto the box (scanned and photo PDFs shrink best).
- Pick a compression level — Recommended suits most sharing and email.
- Press Compress PDF and compare the before/after sizes in the results table.
- Download the compressed copy — your original file is never modified.
Chasing an upload limit?
If a portal insists on, say, 2 MB: try Recommended first, then Smaller, and only then Smallest. If it still doesn't fit, split the document and upload it in parts — most portals accept multiple files, and a split keeps full quality.