Where a 500 KB limit shows up
500 KB caps are common wherever you upload multi-page documents rather than single certificates: bank and fintech KYC checks (statements, proof of address), insurance claims (invoices, reports), rental applications (payslips, references), online government services and many company HR systems. At this size a document of 5 to 15 pages can stay comfortably readable. The trick is to spend the bytes where they matter, and that is what this page automates.
How it hits 500 KB
- Check the size. If the PDF is already under 500 KB, nothing is done and you can download the original.
- Lossless compression first. Files exported from office apps, accounting software and banking websites often carry duplicate fonts, unused objects and uncompressed data. Cleaning that up keeps text, links and digital layout intact and is often enough on its own.
- Targeted image compression. For scans and photo-heavy PDFs, the tool samples up to four pages (first, last and two in between) at different resolutions and qualities, predicts the final size and picks the sharpest setting predicted to fit. It then compresses every page, checks the actual size, and corrects course if the prediction was off.
- Clear outcome. You see the old and new size and the settings used. If 500 KB is impossible at a readable quality, you get the smallest version and a per-page budget.
Size budget per page
| Pages | Budget per page | Typical result for a scanned A4 page |
|---|---|---|
| 3 | about 165 KB | Colour at 150 dpi, high quality |
| 6 | about 82 KB | Colour at 100–120 dpi |
| 10 | about 49 KB | Colour at 100 dpi or black and white at 150 dpi |
| 20 | about 24 KB | Black and white at 85–100 dpi |
| 40 | about 12 KB | Black and white at 60–72 dpi; check small print |
Bank statements and payslips generated as PDFs (not scanned) are text, and a 20-page statement is often only 100–300 KB to begin with. Lossless compression keeps them searchable, which helps whoever reviews them.
Choosing colour or black and white
Leave colour on for documents where colour carries meaning: stamps, highlighted figures, photos and charts. Tick Black and white for typed letters, statements and forms. It usually halves the size of a scan, and the tool spends the savings on a higher resolution, so text gets sharper, not blurrier.
Worked example
An insurance claim portal accepts one PDF up to 500 KB. The claim pack has a 1-page claim form, 6 pages of hospital invoices and a 3-page discharge summary, all scanned on a phone: 10 pages, 14.7 MB.
- Lossless: 14.5 MB, so no real help, as expected for scans.
- Colour image compression: the tool picks 100 dpi at 50% quality, giving “14.7 MB → 468 KB”. Invoice totals and hospital stamps are readable, and the red stamp keeps its colour.
- The reviewer can read every figure, and the upload is accepted first time.
Compared with typical online compressors
| This page | Typical online PDF compressors | |
|---|---|---|
| You set an exact limit (500 KB) | Yes, it searches for the best fit | Usually fixed presets such as “low, medium, high” |
| Tells you if the limit is impossible | Yes, with the smallest size reached | Rarely; you keep guessing |
| Your file is uploaded | No, it stays on your device | Yes |
| Multi-page scans | Free, unlimited | Often capped on free plans |
Before you compress
- Put the pages in the right order and drop duplicates with Organize PDF. Reviewers appreciate it, and fewer pages mean more bytes per page.
- Combine separate files with Merge PDF first if the portal wants one upload.
- Too much for one file? If the portal allows several uploads, Split PDF and compress each part.
- Need searchable text after compressing a scan? Run the result through OCR PDF. The invisible text layer adds only a few KB per page.
Private by design
KYC and claim documents carry account numbers, addresses and medical details. This tool compresses them in your browser: nothing is uploaded, nothing is stored, and there is no sign-up or watermark.