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Compress a PDF to 100 KB

preset to a 100 KB target · realistic about what fits · browser-only

100 KB is a demanding target — the kind an old upload form or a strict portal imposes. This tool is preset to aim for it: drop your PDF and it lowers quality until the result slips under 100 KB, or tells you the smallest it could honestly manage. Runs entirely in your browser; nothing is uploaded.

Drop PDF files here or click to select

Preset target: 100 KB

    no files
    Ready.

    Can every PDF reach 100 KB?

    No — and it's worth saying plainly. A one- or two-page document with mostly text usually can, even after rasterising. A 30-page report or a photo-heavy scan often can't get to 100 KB while staying legible; the ink on the page has a minimum cost. When your file can't reach it, the tool gives you the smallest legible version it produced and shows the real size, rather than quietly returning something still over the limit. If you're close but not under, try splitting the document or aim at 500 KB instead.

    Getting the most out of a 100 KB budget

    Where the 100 KB limit usually comes from

    Almost nobody wants a 100 KB PDF for its own sake. The number is imposed: a government or university portal that has not been touched since 2009, a visa or scholarship application form, a job board's document upload, a tender submission, a bank's KYC form. These forms tend to reject the file with a single unhelpful line and no indication of how far over you are.

    Which is why the verdict here is explicit. You are told the size achieved, and the DPI and JPEG quality that produced it — so if the portal still refuses the file, you know whether you are 4 KB over or 400, and whether there is any headroom left to spend.

    Why this hits the target more precisely than most tools

    The usual approach is a single fixed preset: one quality level, one attempt. If the preset overshoots you get a 22 KB file that is unreadable; if it undershoots you get 140 KB and a rejection. Either way you are guessing and re-uploading.

    This works in two phases instead. First it tries a lossless re-save — a surprising number of bloated PDFs are bloated with structure rather than content, and land under the target with no quality lost at all. If that is not enough it walks down a ladder of resolution-and-quality settings until one fits. Then it goes back: knowing the last setting that was too big and the first that fit, it binary searches the gap between them, keeping the sharpest result that still fits. The point is not to get under 100 KB — that is easy, you can always go to 20 DPI — it is to get under 100 KB while spending as little quality as possible.

    What to do when 100 KB is genuinely impossible

    Some documents cannot get there and stay readable, and no tool on the internet will change that; the ones that claim otherwise are handing you either a file that is still too big or a page of grey mush. In rough order of what to try:

    1. Cut pages. Size is roughly linear in page count. If the portal asked for a certificate and you are uploading a twelve-page pack, extract the one page that matters. This is by far the biggest lever.
    2. Crop the dead space. Auto-crop margins removes scanner borders, which are pure cost at every quality level.
    3. Go grayscale. A colour scan of a black-and-white document is paying for colour it does not use — PDF to grayscale typically takes a third off before compression even starts.
    4. Split and upload in parts if the form allows more than one attachment — Split PDF.
    5. Rescan properly. If the original was scanned at 600 DPI in colour "to be safe", rescanning at 200 DPI grayscale will beat any amount of after-the-fact compression.

    How to compress a PDF to 100KB

    1. Drop the PDF you need under 100 KB. Nothing is uploaded — the whole compression runs in this browser tab.
    2. Leave the target at 100 KB. It is already set; you only change it if you want a different ceiling.
    3. Click Compress & download and watch the status line report each quality step it tries.
    4. Check the verdict. If 100 KB was reachable you see the achieved size; if it was not, you are told the smallest size this document can reach and why, rather than being handed a file that is still too big.
    5. Download and verify the file opens and the text is still legible at the size you need.

    FAQ

    How do I compress a PDF to under 100 KB for free?

    Drop it into the tool above — it's preset to a 100 KB target and works down a quality ladder until it fits, all in your browser with no upload and no signup.

    The result is 130 KB, not 100 — why?

    Because 100 KB wasn't reachable for that document without making it unreadable. The status line shows the smallest achievable size. Reduce the page count or accept the slightly larger file.

    Is the text still selectable?

    At a 100 KB target the pages are almost always rasterised, so text becomes an image — not selectable. That's the trade for hitting an aggressive size. Need selectable text? Aim higher, e.g. 500 KB.

    Will compressing to 100 KB make the document unreadable?

    For a single page of ordinary text, usually not — 100 KB is enough for a legible rasterised page. For a multi-page or photo-heavy document it often will be, and the tool tells you the settings it had to use so you can judge before you send it. Always open the result and read it at the size the recipient will.

    Do you have a file-size or daily limit?

    No. There is no server, so there is no quota, no watermark and no "3 files per hour" — the constraints that most of the sites ranking for this query apply once you are past the first file.

    How do I get a PDF to a different size, like 200 KB or 2 MB?

    Change the number in the target box, or use Compress to a target size, which has quick picks for 100 KB, 200 KB, 500 KB and 1 MB and takes any value you type.

    Is my document uploaded to compress it?

    No. It is rendered and re-encoded in your browser tab. Worth noting given what tends to be attached to portal forms — passports, payslips, certificates — and that the alternative is uploading exactly those to a free compression service.