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 20 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.
A file that is too big for email fails in one of three places: your provider refuses it, the encoded message exceeds the server limit, or the recipient's gateway bounces it. Targeting 20 MB addresses all three for the common cases. For a recipient on a strict corporate system, the 10 MB target is the safer choice; for anything larger than a few hundred pages of scans, a link is the right tool.
Where the 20 MB limit comes from
- Gmail, personal25 MB, measured after encoding
- Outlook.com and Microsoft 365 personal20 MB
- Microsoft 365 business, default33 MB, often lowered by IT
- Corporate Exchange, typical10 MB
- iCloud Mail20 MB before Mail Drop
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 20 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 20 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 20 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 20 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 25 MB is not 25 MB
Mail was designed for text, so an attachment is converted to text-safe base64 before it leaves your outbox. That conversion makes it about 37 percent larger, and the mail server applies its limit to the encoded message. A 20 MB PDF becomes roughly 27 MB in transit and is rejected by a 25 MB cap. The widget below does the arithmetic for your file against each provider.
When it still will not send
Two messages that arrive beat one that bounces
- Split PDF by range into halves
- Each part keeps full quality
- Recipients merge or file the parts as they wish
- Works with every provider and gateway
For anything over about 50 MB
- Drive, OneDrive and iCloud links carry any size
- The file stays under your control and can be revoked
- Some corporate recipients have link previews stripped
- Not an attachment: some workflows and archives need the file itself
Where people use the 20 MB target
- Signed contracts to a client's corporate inboxtext, fits
- Insurance claim packs with photographed evidencemixed
- Property packets to buyers, lawyers and brokersscans and photos
- Quarterly reports and diligence bundlesmixed
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 20 MB cap in front of them.
01Why aim for 20 MB when Gmail allows 25 MB?
Because Gmail measures the encoded message, which is about 37 percent larger than the file. Twenty megabytes on disk is about 27 MB encoded, right at the edge; landing under 20 MB leaves room. Corporate recipients are often behind gateways that cap at 20 MB or lower anyway.
02What if my file still will not fit?
Split it into parts and send two messages, aim for the 10 MB target if the recipient is on a corporate system, or share a link for anything over about 50 MB.
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 20 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.