How the tool reaches an exact size
Most online forms set a hard limit, such as 100 KB, and reject anything above it. The tool gets your PDF just under that limit in up to three steps:
- Smaller pictures, same text. It makes the photos and scanned images inside the PDF smaller and saves them at a lower JPG quality. Text, links and form fields stay as they are. For most PDFs this is enough.
- Sharp black and white for text. If pictures of text (scanned pages, diagrams) would otherwise turn blurry, they are made black and white instead, which keeps letters crisp in far fewer bytes. Photos stay in color, and the result tells you when this happened.
- Pages as images. If that still cannot reach the limit, each page is saved as one image at the highest resolution that still fits. The page looks the same, but its text can no longer be selected or searched, and the result says so.
It always picks the largest file that fits, so you keep as much quality as the limit allows. If your PDF is already small enough, you get it back unchanged.
Black and white helps most with scanned documents: letters stay sharp at sizes where a color scan would turn blurry. Gray makes color scans a little smaller without going fully black and white.
No exact limit? Extreme compress PDF makes the file as small as it can while it stays readable, without asking for a size.
What fits in 100 KB and 200 KB
Results from our test files, so you know what to expect:
| Limit | Result | |
|---|---|---|
| 1-page form with text and a large photo (1.6 MB) | 100 KB | 84.7 KB, text kept |
| 5-page scanned document (2.7 MB), black and white | 100 KB | 92.3 KB, readable at 85 DPI |
| 5-page scanned document, black and white | 200 KB | 149 KB, crisp at 120 DPI |
| 5-page scanned document, color | 200 KB | 176 KB, pages as images at 60 DPI (soft text) |
PDFs made from a word processor, with little or no pictures, are usually small already. Scans and phone photos of pages are what make PDFs large.
Tips for scanned documents
- Scan in black and white or gray if your scanner app offers it; the file starts smaller and compresses better.
- Send only the pages the form asks for. Every page adds size, so a 1-page certificate always looks better at 100 KB than a 6-page bundle.
- Use “Black and white” here for marksheets, certificates and ID scans. Leave it off for color photos.
- Need a photo or signature instead of a PDF? Use the image compressor or resize image in cm for exact KB and cm sizes.