Practical guide 3 min read
How to compress a PDF to 100 KB for an upload form
Get a PDF under 100 KB, 200 KB or 1 MB for an application portal: what the tool tries first, why pages sometimes become images, and what to do if it won't fit.
Make a PDF small enough to email or upload. The photos and scans inside are resized and recompressed, while text and drawings stay exactly as sharp as before. Pick a level, or type the size a form asks for, such as 100 KB, 200 KB, 500 KB or 1 MB.
Drop a PDF here
or
Your files stay on your device. Nothing is uploaded.
Most online PDF tools upload your document to their servers. This one doesn’t: Compress PDF runs entirely in your browser, so contracts, forms, IDs and photos never leave your device. It’s free and adds no watermark, and you don’t need an account.
It depends on what’s inside. Scans and photo-heavy PDFs often shrink by 50–90%, because their images are far larger than a screen or printer needs. A PDF that’s mostly text is already compact and may barely change.
Text, lines and vector drawings aren’t touched, so they stay sharp and searchable. Only the images inside are reduced: Recommended keeps them at 150 DPI, which looks sharp on screen and prints well, and Strong goes down to 100 DPI for the smallest file.
Choose “Target size” and enter the limit. The tool finds the highest image quality that fits, and only saves pages as images if shrinking the images isn’t enough. It aims under 100,000 bytes for 100 KB and 1,000,000 for 1 MB, so the file passes however the form counts a kilobyte.
A scan of one or two pages usually can. Every page needs a few kilobytes even at low resolution, so a long document may not fit: split it or delete the pages the form doesn’t need first. If the target can’t be reached, the tool tells you how small it could get.
A scan is already a picture, so nothing is lost. In a PDF with real text, the fonts alone can take more than 100 KB, and saving each page as a compact image is then the only way under the limit, at the cost of selectable text. At 500 KB or more, shrinking the photos is usually enough, and the result tells you if pages had to become images.
It has no large images to shrink, or it was compressed already. Most of a text PDF’s size is its fonts, which can’t be reduced without changing how the text looks. Target size can go further by saving pages as images, as a last resort.
Scan in grayscale at 150–200 DPI rather than colour at 600 DPI, and crop away the scanner bed around the page. A clean, flat scan compresses far smaller than a phone photo with shadows.
Upload only the pages the form asks for, using Extract PDF Pages. Fewer pages leave more of the limit for each one, so they come out sharper.
No. Every tool runs in your web browser, so your files are read, changed and saved on your own device and never sent to LabAnvil or anyone else. Once the page has loaded, the tools even work offline.
Free, with no watermark, no daily limit and no account.
18 free PDF tools that run in your browser: merge, split, compress, convert, edit, sign and fill in PDFs without uploading them anywhere.
A little guidance
Practical guide 3 min read
Get a PDF under 100 KB, 200 KB or 1 MB for an application portal: what the tool tries first, why pages sometimes become images, and what to do if it won't fit.
Practical guide 3 min read
Shrink the photos and scans inside a PDF and leave its text sharp: which compression level to pick, what changes, and what to do when a PDF won't shrink.
Practical guide 3 min read
Combine phone photos, scans and screenshots into a single PDF, in the right order, at a page size that prints properly.
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