Why a form asks for a PDF under a set size
Online application forms keep uploads small so that thousands of applicants can submit on the last day without the site slowing down. This comes up on government recruitment and exam applications (SSC, UPSC, state public service commissions, banking exams), on admission forms such as NEET, on scholarship portals and in passport applications. Each portal sets its own limit and can change it from one year to the next, so the number to type here is always the one printed next to the upload button, not one copied from a forum.
A PDF straight from a phone scanner app or a photocopier is often 1 to 5 MB for a single page, far over a limit of 100 or 200 KB. Typed documents saved from Word are usually much smaller already.
How this tool gets a PDF under the limit
- A lossless rewrite first. The PDF is rebuilt with its internal parts packed more tightly. Nothing you can see changes and text stays selectable. For typed documents this alone is often enough.
- Redrawing the pages, only if needed. If the rewrite is still too big, every page is drawn as a picture and saved as a JPG inside a new PDF. The tool tries several sharpness levels (DPI) and JPG qualities and keeps the sharpest combination that fits. With black and white ticked, each page becomes a crisp black and white image instead, which keeps printed text sharp at sizes where a colour JPG would blur; when a colour result comes out soft, the tool makes a black and white copy as well so you can compare. Text in a redrawn copy becomes part of the picture, so it can be read but not selected.
Every page is kept, in the same order and at the same page size. The result tells you which of the two steps was used.
Which size to pick
Use the exact limit from the form. The shortcuts cover the common ones: compress PDF to 50 KB for a single certificate or ID proof, compress PDF to 100 KB for a mark sheet or a scanned page, and compress PDF to 200 KB for a document of several pages. If the form wants a photo or signature as JPG rather than a PDF, the image tools do the same job for pictures.
When a PDF will not go small enough
- Upload only the pages the form asks for. Twenty pages will not fit in 50 KB at a readable quality.
- Tick black and white for scans of printed paper. Colour adds bytes and rarely helps a form.
- Rescan at a lower setting, such as 150 or 200 DPI, instead of 600.
- If the PDF is locked with a password, remove the password first, then compress the unlocked copy.
The tool aims a little under the number you type, counting 1 KB as 1,000 bytes, so the file passes whether a portal counts a KB as 1,000 or 1,024 bytes.
Built on two open-source projects that run in your browser: qpdf, compiled to WebAssembly, for the lossless rewrite, and Mozilla's PDF.js to redraw pages when that is not enough.