A PDF is not a photo. Shrinking one can cost you the selectable text, the form fields and any digital signature, so the useful question is not "how small can it go" but "what am I allowed to lose". Get that right and 500 KB is usually easy.
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There are two ways to shrink a PDF. Shrinking the images inside it keeps the text selectable, the links live and the form fields fillable. Rendering each page to a picture makes the file far smaller and destroys all three. Pick deliberately, because the second one cannot be undone.
Half a scanned document is often a blank page, a duplicate or an annex nobody asked for. Deleting, reordering or extracting a page range costs nothing in quality; compressing the same pages twice always does.
A 500 KB file that lost a page is worse than a 700 KB file that kept it. Reopen the result, confirm the page count, and try selecting a sentence — if the text highlights, the file is still text, not a picture of text.
Most oversized PDFs are oversized for one reason: scanned pages stored as high-resolution images. A single A4 scan at 600 DPI is several megabytes on its own, so a ten-page document can pass 30 MB without containing a byte of actual text.
Text, fonts and vector lines are cheap. Photographs and scanned images are expensive. Knowing which one you are holding tells you whether compression will help: image-heavy files drop dramatically, while a text-only PDF that is already 400 KB has little left to give and does not need your attention.
Compression preserves the text, the page count and the layout. Pages can be reordered, rotated, removed or extracted as a range before you compress, so you are not paying bytes for a page you will not submit.
Digitally signed documents are detected and password-protected files are handled without storing the password. An image-only copy exists as an explicit option that warns you first, because it drops selectable text, links and signature validity.
The result is reported with its size in bytes, real format and page count, and each requirement you entered is marked as meets, does not meet, not checked or needs your review. The original file is never modified — saving writes a new copy.
Compress the images inside the PDF rather than rasterising the pages, then check the size of the file you produced. UploadReady reports the measured size and page count of the compressed copy and marks the requirement you entered as met or not met.
Any change to a signed document invalidates the signature, including compression. UploadReady detects digitally signed documents and warns you before it writes a modified copy. If the signature has to stay valid, submit the original.
Not if the text is preserved during compression. It does if the pages are rasterised into images. The quick check is whether you can still select and search a sentence in the result. UploadReady offers an image-only copy as an explicit, clearly labelled option that warns you first, rather than doing it silently.
Yes. The PDF never leaves the device: no upload, no account, no cloud storage and no AI service. That matters for contracts, medical letters and anything containing an identity number.