How to Compress a PDF to 100 KB, 200 KB, 500 KB or 1 MB (Free, No Upload)

Why portals ask for small PDFs, and why yours is so big

Government recruitment sites, university admission forms, scholarship portals, bank KYC pages and visa applications often set a strict upload limit: 100 KB for a certificate, 200 KB for a mark sheet, 500 KB or 1 MB for a set of documents. The limit keeps their servers fast and their storage costs down. The problem is that the PDF you made a few minutes ago with a phone scanner app is often 2 MB, 5 MB or more.

The reason is almost always pictures. A PDF that you typed in Word or exported from a billing app stores letters as text, which is tiny. A scanned PDF stores each page as a photograph. A modern phone camera captures a lot of detail, so every page can easily be a million or more pixels in full colour, and the PDF simply wraps those photos. Ten scanned pages can therefore be far heavier than a hundred typed pages.

• High resolution: scanner apps often save at 300 dpi or more, which is far more detail than a portal reviewer needs to read a certificate.
• Full colour: a black-and-white mark sheet saved in colour carries three channels of data for every pixel, including the faint yellow of the paper.
• Light compression: some apps save pictures with very little compression so they look perfect, at the cost of size.
• Extras: embedded fonts, duplicated images, form fields and editing history can add weight to PDFs made in office software.

Once you know the weight is in the pictures, the fix is clear: make the pictures smaller and lighter without making the words unreadable.

The quickest way: set the exact size with Target-size PDF

If a portal gives you a number, use Target-size PDF. Instead of guessing a compression level and trying again and again, you tell it the size you need and it works towards that size for you.

It works in two stages. First it tries picture compression that keeps the text layer intact: it re-encodes and downsizes the images inside the PDF while leaving typed text, links and vector graphics as they are. For many documents, especially ones that mix typed text with a logo or a photo, this is enough. If the file is still above your target, it moves to the second stage and rasterises pages, which means it redraws each page as a single image at a lower resolution. That almost always reaches the target, but the text on those pages is no longer selectable or searchable.

TipAsk for a little less than the limit. If the portal says 'maximum 200 KB', target around 190 KB. Some portals count a kilobyte as 1,000 bytes and others as 1,024 bytes, and a tiny margin avoids a frustrating rejection.

When to use Compress PDF instead

Sometimes you do not have a hard number. You just want the file lighter for email or storage. In that case Compress PDF is simpler: you pick a level and it does one pass. The levels behave like this:

A practical approach is to start with Recommended. If the result is still too large, try Strong. If you need a precise ceiling, switch to Target-size PDF rather than repeating Strong over and over, because compressing an already compressed picture again tends to damage quality faster than it saves space.

Will my text stay selectable after compression?

This depends on what kind of PDF you start with and how far you need to shrink it.

• Typed or exported PDFs (from Word, Google Docs, Tally, a bank's statement download): the text is real text. Picture compression leaves it alone, so it stays sharp at any zoom and you can still select and search it.
• Scanned PDFs: the text was never text in the first place, it is part of a photo. Unless your scanner app added OCR (a hidden text layer), there was nothing to select before compression and there will be nothing after.
• Scanned PDFs with OCR: the hidden text layer usually survives picture compression. If the tool has to rasterise the page to hit a very small target, the OCR layer is lost.

For most application portals, selectable text does not matter. A human reviewer looks at the page. What matters is that names, dates, roll numbers and signatures are clearly readable. If you do need searchable text, for example for a contract you will refer to later, keep an uncompressed copy for yourself and only send the compressed one.

Watch outAlways keep your original file. Compression that reduces picture detail cannot be undone, so you cannot get the original sharpness back from the small copy.

Typical size targets and what to expect

Results vary with the number of pages, how busy each page is and whether it is in colour, so treat this as a rough guide rather than a promise.

If you are trying to fit ten colour pages into 100 KB, the result will be hard to read whatever tool you use. In that situation it is better to reduce what goes into the file than to crush the quality.

If the file still will not go small enough

1. Remove pages the portal did not ask for. Blank backs of pages and instruction sheets add weight. Use Organize PDF to delete or reorder pages, then compress again.
2. Rescan in greyscale or black-and-white. Most certificates and mark sheets read perfectly without colour, and the file is much lighter.
3. Lower the scan resolution. Around 150 dpi is usually plenty for on-screen reading. Many scanner apps have a quality or size setting.
4. Crop the edges. A photo of a document that includes the table and your fingers wastes pixels on things nobody needs.
5. Split the document if the portal allows several uploads. Split PDF by size cuts a file into parts that each stay under a limit.

If your source is a set of photos rather than a PDF, it often helps to shrink the photos first and then combine them. Our guides on reducing photo size to 20 KB or 50 KB and converting JPG to PDF cover that route step by step.

Check the file before you upload it

A file that meets the size limit but is unreadable can still get your application rejected later, sometimes after the deadline has passed. Before you upload, take thirty seconds to check:

• The file size in your file manager is below the limit, not just close to it.
• Your name, date of birth, registration number and any amounts are readable at normal zoom.
• Signatures, seals and photos are visible and not blotchy.
• All the pages are there and in the right order.
• The file opens without asking for a password. Many portals cannot read protected PDFs, so if your source was password-protected, see our guide to Aadhaar PDF passwords for how to open and resave it.

Because the tools run in your browser, you can repeat the process as many times as you like with different targets, and none of your certificates or ID documents leave your device.