How to compress a PDF to 200KB, 500KB or 1MB
Open the file in the compressor, pick the setting that lands under your limit, and check that the smallest print still reads. A text PDF usually fits any of these targets as it is; it is scans and photographs that need the work, and the trick is to lower the image resolution before you lower the image quality.
Compress PDF shows the size before and after, so you can stop as soon as you are under the limit. Compress PDF
Reaching a size limit, step by step
- Find the real limit on the upload page and write it down; the number varies by portal and sometimes by document type.
- Open the PDF in the compressor and look at the starting size. If it is already under the limit, upload it unchanged.
- Choose the middle setting first. For a scan, that usually drops the file to a quarter of its size with no visible loss.
- Check the result: zoom to the smallest text and read a line. If it is clear and under the limit, download it.
- If it is still too large, lower the resolution rather than the quality; a page scanned at 300 dots per inch rarely needs more than 150 for reading on screen.
- If a single page still will not fit, split the file and upload the parts, which most portals accept.
Common upload limits
| Where | Typical limit | What usually fits |
|---|---|---|
| Job and recruitment portals | 200KB to 2MB a file | A text CV fits easily; scanned certificates need compressing |
| Visa and immigration portals | 300KB to 2MB | A passport scan as one page at modest resolution |
| University applications | 500KB to 5MB | Transcripts fit; photographs of certificates are the usual problem |
| Government forms | 1MB to 10MB | A filled form almost always fits without compressing |
| Email attachments | 20MB to 25MB in total | Several documents together; compress the scans, not the text PDFs |
| WhatsApp documents | 100MB | Rarely the limit; the mobile data bill is |
Limits change without notice. Treat this table as a guide to what is normal, not as the rule for the portal in front of you.
Why text PDFs are small and scans are not
A page of typed text stored as text is a few kilobytes: the letters are instructions to draw glyphs, not pictures of them. A scanned page is a photograph of paper, and a photograph of an A4 sheet at 300 dots per inch is several megabytes before compression. Every size problem in practice is an image problem, which is why the settings that matter are resolution and image quality, and why a text PDF rarely needs touching.
Which setting reaches which target
For a one or two page scan, the middle setting usually lands between 300KB and 800KB, which covers most 1MB and 500KB limits. For 200KB, drop the resolution to around 150 dots per inch and accept a slightly softer image; text stays readable well below that. For 100KB, the separate guide covers the cases where it cannot be done without converting the page to black and white.
Colour costs size. A black text document scanned in colour carries three channels of nearly white paper for nothing. Converting to greyscale often halves the file before any other setting is touched, and loses nothing a reader will notice.
How to compress a PDF to 100KB, and when you cannot
What compression does to a document
Lowering image quality adds the blockiness you know from an over-compressed photograph; on text it shows first as grey halos around letters. Lowering resolution keeps the letters clean but makes very small print soft. For documents, resolution is the better lever, because a clerk reading a scan needs letter shapes, not smooth gradients. Nothing here changes a text PDF’s words, and nothing is sent anywhere: the whole job happens in your browser.
When compressing is the wrong answer
A portal that rejects a 40KB file for being over the limit is checking something else, usually page count or dimensions. A scan that is too large because it holds twenty pages is better split than squeezed, and a photograph that is too large because it is a photograph is better rescanned as a document. If the limit is tiny and the document is long, ask the recipient whether they will accept two parts; most will.
Questions people ask next
How small can a PDF get without becoming unreadable?
A single text page can go below 20KB. A scanned page keeps reading comfortably down to about 80KB at 150 dots per inch in greyscale. Below that, the choice is between black and white conversion and losing legibility, which the 100KB guide covers.
Does compressing reduce the number of pages?
No. Compression changes how each page is stored, not how many there are. If a portal counts pages, split the file instead.
Will the recipient be able to tell the file was compressed?
On a text PDF, no, because nothing about the text changes. On a scan, a careful eye may notice softer edges on small print at the lowest settings. At the middle setting the difference is invisible on screen.