"File too large." It's usually the last thing standing between you and a submitted application. Most email services stop at around 20 to 25 MB per message, and many online portals (universities, insurers, government sites) cap uploads at 2, 5 or 10 MB. A few phone-scanned pages can blow past that easily. This tool shrinks a PDF on your own device, so the document is never uploaded anywhere.
Two ways to compress
Light rebuilds the file more efficiently without touching what's on the page. Text stays sharp and selectable, and nothing looks different. It helps most with PDFs exported from Word or design software, which often carry unused baggage. Sometimes the saving is small, and that's honest: if your PDF is already lean, there just isn't much to remove.
Strong redraws every page as an image at the resolution and quality you choose. This is what you want for scans and photographed documents, where the pages are images anyway. It can shrink a 15 MB scan to well under 2 MB. The trade-off is that text in the result can't be selected or searched. For a scanned ID or a signed form that rarely matters; for a 40-page report people need to search, use Light.
Getting under a specific limit
Start with Strong at 150 dpi and Medium quality, then check the size shown. Still too big? Drop to 100 dpi or Low quality. For text-heavy scans, 150 dpi is usually the sweet spot where everything stays readable on screen and on paper. Below about 100 dpi, small print starts to blur. If the document is just a few pages and still too big, the black and white option in PDF to Grayscale often produces tiny files for plain text scans.
A quick way to estimate what you'll save
Look at where the size comes from. A text-only report of fifty pages is often under 1 MB, so there isn't much to squeeze. A single phone-photographed page can be 3 to 5 MB because it's one big image. Scans and photos are where Strong shines, often cutting a file to a tenth. If your PDF is a mix, such as a report with several large photos, try Light first and move to Strong only if it still doesn't fit.
Other ways to make a PDF lighter
- Remove pages you don't need. Blank backs and cover sheets add up. Delete PDF Pages takes them out in a click.
- Crop away dark scanner borders with Crop PDF, which also makes pages look tidier.
- Resize oversize pages. A scan accidentally saved at A3 is four times the area it needs to be. Resize PDF brings it down to A4.
- Split a huge file. If a portal allows only a small file at a time, Split PDF divides it into parts.
What not to do
Don't compress a file again and again hoping to reach a tiny size; every Strong pass on an already-compressed scan loses a little more detail. If you need to repeat the process, go back to your original and choose the stronger setting once. Equally, keep an uncompressed copy of anything important. A compressed version is for sending; the original is for keeping. And if the compressed result would be larger than the original, the tool tells you instead of handing you a worse file.
After compressing
If the file is going to several people and you want to know it hasn't been altered later, see the hash generator, which creates a fingerprint you can share alongside it. If it contains personal details you don't want to pass around, take a look at Redact PDF and the metadata editor, because file properties can reveal author names and software details you didn't mean to include. As with everything here, compression is done by your browser; the PDF never leaves your device.
Typical limits you'll run into
Every service has its own ceiling, and it's worth checking before you start. Free email accounts commonly accept attachments of around 20 to 25 MB, though some corporate systems are stricter. Application portals for jobs, courses and visas often allow between 2 and 10 MB per file, and some insist on a single file. Messaging apps compress files themselves and may reject large documents. If you don't know the limit, aim for under 2 MB for a short document and under 10 MB for a long one; that works almost everywhere.
It also helps to compress to a target in two steps: first try Light, which costs you nothing in quality, and only then step up to Strong. You'll often be surprised by how little you need to give up to get under the line.
A worked example
A phone-scanned 6-page expense report is 14 MB and your finance system accepts 5 MB. Open it, choose Strong, 150 dpi and Medium quality, and compress: the result is 1.1 MB. Open the new file and zoom in on the receipts to make sure the small print is still readable. It is, so you upload it. If a receipt looked blurry, you'd go back to the original and choose 200 dpi, still giving a file well under the limit.