Fit your PDF under any size limit

Start from the number on the screen

It is twenty minutes before a rental application portal closes, and your twelve-page scan of pay slips and ID, a file called application-docs.pdf weighing 9.4 MB, bounces back with a red line: maximum attachment size 2 MB. Nothing is wrong with the content. The portal simply refuses to store anything heavier, and it will keep refusing until the bytes fit.

That red line is the only setting that matters. Forget quality sliders and vague low-medium-high labels: read the cap, type that exact number as your target, and let the tool work toward it. A 2 MB cap means asking for 2 MB or a touch less, a 500 KB job portal means asking for 500 KB, a visa field means 200 KB. The target is a ceiling, and the finished file lands below it, never exactly on it.

One detail saves a second attempt. PDFGym counts a kilobyte as 1,024 bytes, so a 200 KB target draws the line at 204,800 bytes. Some upload forms count a kilobyte as a flat 1,000 bytes, which makes their cap sit about 2% lower than yours. If a file that looks like it fits still gets rejected, lower the target a little, 195 KB instead of 200, and run it once more.

Shrink it in four moves

1. Open the compress tool in your browser. Nothing to install, no account to create.
2. Click Choose a PDF or drag the file onto the page. It opens locally, inside the tab.
3. Pick a size chip such as 100 KB, 500 KB or 1 MB, or type the exact cap from the form, in KB or MB.
4. Press Compress, read the verdict with the final size, then download the file when the numbers satisfy you.

The verdict line is worth a glance before you download: it states the finished size, how much lighter the file became, and which technique did the most work. When the result lands above your target, that verdict tells you what to attack next instead of guessing.

Common caps and the target to type

Portals and inboxes cluster around a handful of ceilings. Find yours below and type the number on the right.

Caps you meet often have their own preset pages that open with the number already filled in, so bookmark one per recipient and skip typing entirely.

What the tool squeezes, in order

Behind the single button, four techniques take turns against your file. A structural re-save rebuilds the document into a fresh file and drops leftover data from past edits. Image downsampling re-encodes oversized photos and scans at a resolution screens actually use. Font subsetting trims each embedded font down to the characters the pages really draw. And a raster redraw, held back as the last resort, re-renders stubborn pages and writes their text back as an invisible layer so the words stay selectable.

You never pick among them. The engine tries each in turn and keeps the smallest result that clears your ceiling, then names the winner in the verdict. That name is a diagnosis: when images won, your file was photo-heavy; when the structural pass won, the file was mostly clutter. If curiosity bites, the size breakdown tool shows the same answer before you compress, page by page.

The compression level chips, Highest, Average and Low, are shortcuts that set the target from the file itself: roughly a quarter, a half, or three quarters of the original weight. Average suits most uploads; reach for Highest only when a strict cap leaves no other choice, and check the side-by-side preview before downloading. The quality guide walks through that trade in full.

Mistakes that waste a run

Typing the size you have instead of the size you need. The box asks for the ceiling, not the current weight. Read the form first, then type its number.

Compressing the wrong file. People shrink contract-final.pdf while the portal wants contract-signed.pdf, then wonder why the upload still fails. Check the file name in the tool before pressing the button.

Ignoring the side-by-side preview. Highest level on a photo-heavy scan visibly smooths images. Glance at the preview crops; if faces turn to wax, step back to Average and accept a roomier target or fewer pages.

Squeezing an encrypted file. A PDF that asks for a password just to open resists the rebuild tricks compression relies on. Unlock it first, then compress the unlocked copy.

Sending the file without opening it. Every candidate is opened again and checked against the original before download, but your eyes are the last check that matters. Open the download, skim each page, then send.

When the browser is the wrong place

An online tool, even one that uploads nothing, is not always the right answer. If your employer or client contract forbids opening a document outside approved software, keep the file in the approved app and ask IT for the sanctioned way to shrink it; policy beats convenience.

If the PDF is destined for professional print, do not compress it at all. Press workflows measure resolution, color spaces and bleeds, and a file tuned for a screen will fail those checks or print soft. Send the original to the printer and let their preflight decide.

And if the file needs to shrink tenfold but every photo must stay pixel-perfect, no compression setting squares that circle. Split the document into parts that each fit the cap, or ask the recipient whether a shared folder link works instead of an attachment.