Drop the PDF and press the button. The tool works in three stages, cheapest first, and stops at the first one that gets the file under 10 MB.
Images are recompressed in place first, so text, links and forms stay exactly as they were. Only when a file still will not fit are the pages rebuilt as images, and even then an invisible text layer keeps the words searchable. A file already under the cap is handed back untouched. If your file is already small enough, you do not need this tool.
The 10 MB ceiling is the default on Outlook.com and Microsoft 365 personal accounts, on most corporate Exchange servers, and on iCloud Mail before it diverts an attachment into a link. It also appears on some state court e-filing systems. Almost anything under fifty pages fits at the first attempt; a two-hundred-page colour scan is where the ladder does its work.
Where the 10 MB limit comes from
- Corporate Exchange servers and Microsoft 365 personal accounts10 MB per message
- iCloud Mail before Mail Drop takes over10 to 20 MB
- Some state and county e-filing systems10 MB per document
- Client portals and secure message systems10 MB
- Government tender and procurement uploads10 MB
Caps like this are rarely revisited once set. They are written into a portal's upload form at launch, sized for the storage and bandwidth of the day, and outlive both. The practical response is not to argue with the number but to produce a file that clears it while staying readable, which is what the ladder below does.
How the tool hits 10 MB
Add the PDF
Drop it or browse. It is read into browser memory; nothing is uploaded, so a slow connection makes no difference.
Stages one and two: tidy, then the images
Unused objects, thumbnails and stale metadata go first, which costs nothing at all. Then the pictures inside the file are recompressed in place, starting at 200 ppi, while your text, links and form fields are left exactly as they were.
Stage three, only when it is needed
If the images were not where the weight was, the pages are rebuilt as pictures with an invisible text layer behind them, so the words stay searchable. It probes at 150 dpi, works out the resolution that should fit, and will not go below 60 dpi.
Download, and read the result line
It shows the final size and which stage produced it. If none fitted, you still get the smallest attempt, labelled honestly, rather than a file that silently missed the target.
Structure, then the images in place, then the pages as pictures. It stops at the first stage that fits.
Untouched at the first two stages. If the pages do get rebuilt, an invisible text layer keeps them searchable.
The IDs, forms and statements people compress for portals never leave the device.
What fits in 10 MB, and what does not
The honest answer depends on page count and on what is on the pages. Text pages are cheap because a rendered page of black text compresses extremely well as a JPEG. Colour scans and photographs are expensive because every pixel carries information the encoder has to keep. The estimator uses typical figures to show which attempt your file is likely to land on.
When it cannot reach 10 MB
Some documents will not fit legibly, and the tool says so rather than pretending. When the result line reports a miss, three moves usually solve it:
- Split first. Use Split PDF to break the file into parts and compress each. Most portals accept several attachments even when each one is capped at 10 MB.
- Rescan the source. A fresh 150 dpi greyscale scan compresses far better than a colour scan that has already been through one compressor. Every pass costs quality, and the first pass should start from the cleanest source.
- Check the real limit. Portals sometimes state one number and accept another. Read the fine print, or try a slightly larger file before compressing harder than you need to.
Why 10 MB on disk is not 10 MB in the mail
Email cannot carry binary files directly. Every attachment is base64 encoded before it is sent, which inflates it by roughly 37 percent, and the gateway measures the encoded message. A 9 MB PDF on your disk is about 12.3 MB on the wire, over a 10 MB limit. The target on this page is the file size, so aim for the size that clears the cap after inflation: about 7 MB on disk for a strict 10 MB gateway.
Where people use the 10 MB target
- Signed agreements to a client on corporate mailtext, fits
- Inspection and audit reports with photosmixed, attempt 1 or 2
- State court filings with exhibitsmixed
- Design deliverables that must arrive as attachmentsimages
Why this runs in your browser
The files people compress for portals are the ones that identify them: passports, ID cards, certificates, bank statements, tax forms. Uploading them to a compression website in order to upload them again to the portal doubles the exposure for no benefit.
The tool is right above
Everything on this page runs in your browser. Scroll up, drop the file, and keep it on your machine.
Common questions
The questions people have with a 10 MB cap in front of them.
01Why 10 MB specifically?
It is the default attachment ceiling on corporate Exchange, Microsoft 365 personal accounts and iCloud Mail, and files above it regularly produce undeliverable-mail bounces on corporate gateways.
02My file is 9.5 MB and still bounced. Why?
Base64 encoding adds about 37 percent in transit, so a 9.5 MB file is about 13 MB on the wire. Aim for 7 MB on disk for a strict 10 MB gateway, or split the document into two messages.
03Will the text still be readable?
For text documents, yes, and usually at the first attempt. For colour scans and photo-heavy pages, later attempts soften the image visibly. The result line tells you which attempt produced the file, and the estimator above predicts it.
04Will the text still be selectable?
Usually, yes. The first two stages leave the text exactly as it was. If the file only fits by rebuilding the pages as pictures, an invisible text layer goes behind them so the words can still be searched and copied.
05What if the file cannot get under 10 MB?
You still get the smallest attempt, with the result line stating the final size honestly. Split the file into parts, or rescan the source in greyscale at a lower resolution, and try again.
06My file was already small. Why did it grow?
The tool checks the size first and hands a file that already fits straight back, untouched. If the file is already under the cap, send it as it is.
07Are my files uploaded anywhere?
No. Rendering and compression run in your browser. The file never leaves the device.
08Is it free?
Free. Every tool, unlimited use, no signup.