How to compress a PDF to 300 KB
- Tap Choose a PDF to shrink and pick your document.
- The target is set to 300 KB already, so tap Compress to 300 KB.
- Read the notes underneath — they say what changed in your particular file.
- Save the compressed copy under a new name.
What survives at 300 KB, and what does not
At this size a colour scan is still a colour scan. Photographs stay recognisable, seals and letterheads keep their colour, and printed text holds up under zoom. What goes first is fine detail in a busy photograph — the weave of a cloth, the leaves of a tree — because that detail costs the most bytes and matters the least on a form.
Making a PDF smaller means writing the document out fresh, and two things do not survive that: bookmarks, and the fillable parts of a form. Answers already typed into a form stay visible on the page and simply stop being editable. Your pages, their text, their images and their links all come through, and the tool names whichever of the two your file actually had rather than warning about both every time.
Naming a size instead of moving a slider
Most compressors offer low, medium and high, and leave you to guess which one will clear the limit on the form. Every wrong guess costs another trip through the upload page. Naming the number instead turns it into arithmetic the tool can do: it works down the quality ladder until it finds the best version that fits, and stops there.
The three levels are still worth having when no particular figure is in your head — they are on the main compress page as Light, Recommended and Strong. Use those when you simply want a smaller file, and use this page when a portal has told you a number.