Compress PDF to 100KB
Compress PDF to 100KB online free for scanned forms and ID uploads. Finds the best quality that fits, in your browser, so your PDF is never uploaded.
Drag & drop PDF files here
Everything happens in your browser: your PDFs are never uploaded anywhere.
MonsterConvert lowers quality as little as it can to get the file at or under this size.
How to compress a PDF to 100KB
Three steps, all in your browser.
Add your PDF
Drag and drop a PDF, or click to browse. It stays on your device.
Check the 100KB target
The size is already set to 100KB. Change it if you need a different limit.
Compress and download
Download a PDF at 100KB or under, with as much quality kept as possible.
When you need 100KB
100KB is a common ceiling for scanned certificates, ID cards, and single-page forms on government, exam, and scholarship portals. A scan is mostly one big picture per page, so it usually shrinks a lot. A PDF that is mostly text may not get this small without being flattened into pictures.
What to expect at 100KB
As a rough guide, 100KB holds about one scanned page at moderate resolution, or several pages of mostly text. A multi-page scan usually needs a larger size or flattening.
Tips for getting a PDF to 100KB
- Scan in grayscale at around 150 dpi when color doesn't matter: it makes a scan several times smaller before compression even starts.
- Split a long document and compress the parts separately if the portal has a per-file limit.
- Turn on "Convert images to grayscale" for black-and-white forms and certificates.
Nothing uploaded
PDFs are compressed in your browser, so private documents never leave your device.
Highest quality that fits
It searches for the best quality that keeps the file at 100KB or under, instead of guessing a setting.
Text stays sharp
Only the images inside are recompressed, so text stays selectable unless you allow flattening.
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Frequently asked questions
Drop your PDF into the box above and click Compress. The size is already set to 100KB: MonsterConvert works out how far the images inside can be recompressed to get the file at or under that size, and keeps as much quality as it can. Then download the result.
Most of a PDF's size is usually the pictures inside it: scanned pages and photos. Images stored as JPEG are recompressed at a lower quality and, if they are larger than they need to be, at a smaller pixel size. Text, fonts, and links are not touched, so text stays sharp and searchable.
A PDF made from a document (Word, LaTeX, a web page) is mostly text and fonts, not images, so there is little to recompress. Images stored in other ways, such as PNG-style images, images with transparency, or CMYK images, are also left as they are, and the result tells you how many images were skipped. To shrink a text-only PDF much further, use the Maximum level, which flattens every page into a picture.
Flattening turns each page into a picture of itself. That can reach very small sizes, but the text can no longer be selected, searched, or copied, and links stop working. It is off unless you choose Maximum or allow it when a size target can't be met any other way.
Each scanned page is a full-page picture, and five of them rarely fit in 100KB at a readable quality. Try grayscale, allow flattening, or split the file into smaller PDFs.
Sometimes. If most of its weight is embedded fonts rather than images, recompressing images does nothing, and only flattening can get it smaller. The result tells you when that is the case.
Some PDFs can't get to 100KB without flattening (for example, long text documents). When that happens the result says it got as close as it could, instead of claiming success, and you can choose to allow flattening and try again.
The result is at or under your target, as close to it as the search gets, so quality is not thrown away for nothing. MonsterConvert counts 1 KB as 1,000 bytes, so the file also passes a site that counts 1,024. If the PDF is already smaller than the target, it is returned unchanged.
Rewriting a PDF invalidates a digital signature and can break PDF/A conformance, so you'll see a warning when either is detected. Password-protected PDFs can't be compressed: unlock them in your PDF viewer first (open it and Print -> Save as PDF), then add that copy.
No. The PDF is compressed inside your browser using WebAssembly, so it never leaves your device. That makes it safe for contracts, IDs, and other private documents.
Because everything runs on your device, very large PDFs need a lot of memory. Files over 50 MB show a warning, and files over 250 MB are refused. If yours is that big, split it first and compress the parts.