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 3 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.
Three megabytes holds about seventy pages of text, twenty pages of greyscale scanning, or a dozen colour pages. Those are very different documents, and the one in front of you is usually a mixture: a few scanned pages inside a longer text document, or a report whose photographs carry most of the weight. Working out the per-page budget tells you which part of the file to deal with.
Where the 3 MB limit comes from
- Government e-forms and licence applications3 MB per upload
- Older mail systems and mailing lists3 MB per attachment
- Insurance and claims portals2 to 3 MB
- Medical records and referral uploads3 MB per document
- Ticketing and support attachments3 to 5 MB
Three megabytes is the size systems choose when they want to accept a real multi-page document without accepting a raw scan of one. It is roughly what a twenty-page greyscale scan weighs at a sensible resolution, which is not a coincidence: the limit was set by somebody who looked at the documents people were actually sending and picked a number just above the reasonable ones.
How the tool hits 3 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 3 MB, and what does not
The mixture on the pages decides everything. Text costs about forty kilobytes a page, a page with charts and a logo about a hundred and ten, a greyscale scan a hundred and thirty, and a colour scan closer to two hundred and forty. Multiply by your page count before you compress and you will know which attempt to expect.
When it cannot reach 3 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 3 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.
Budget per page, not per file
Divide the cap by the page count and you get the only number that matters: how much each page is allowed to weigh. Three megabytes over ten pages is a generous three hundred kilobytes a page, enough for full colour at a resolution nobody will question. The same three megabytes over sixty pages is fifty kilobytes a page, which is a text budget, and no amount of compression turns sixty colour scans into a text budget.
The practical use of this is that it tells you where to look. If the budget per page comes out above two hundred kilobytes, the file should fit at the first or second attempt and anything that goes wrong is a structural problem rather than an image one. If it comes out below sixty, the document is being asked to be a text document, and the honest fix is either to split it or to accept that the scanned pages will be rebuilt as pictures.
The middle range is where judgement is needed, and the useful move there is to stop thinking of the file as uniform. A sixty-page report with four scanned exhibits is not sixty pages at fifty kilobytes. It is fifty-six cheap pages and four expensive ones, and the four are where the whole decision sits. Compressing the document as a whole spreads the loss evenly across pages that did not need it. Extracting the exhibits, compressing those, and merging the result back gives a better document at the same size.
The tool above works on the file as a whole, because that is what a size cap applies to. If the per-page arithmetic tells you the weight is concentrated, Split PDF and Merge PDF between them let you spend the budget where it earns its keep.
Where people use the 3 MB target
- Licence and permit applications10 to 20 pages
- Medical referrals with scanned results5 to 15 pages
- Insurance claim bundles10 to 30 pages
- Reports with photographs20 to 40 pages
Why this runs in your browser
Files at this size are usually whole case bundles: a claim with its evidence, a referral with its results, an application with its supporting documents. That is a lot of personal information to hand to a website whose only job is to make it smaller.
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 3 MB cap in front of them.
01What fits in 3 MB?
Around seventy pages of text, twenty pages of greyscale scanning, or a dozen colour pages. Mixed documents land in between.
02How do I know if my file will fit?
Divide 3 MB by the page count. Above two hundred kilobytes a page, expect a clean first attempt. Below sixty, expect the pages to be rebuilt as pictures.
03My document is mostly text with a few scans. What should I do?
Deal with the scanned pages rather than the whole file. Split them out, compress those, and merge the result back so the text pages keep their original quality.
04Why did a short document fail when a long one passed?
Page count matters less than what is on the pages. Four colour scans outweigh forty pages of text.
05My file is already under 3 MB. Do I need this?
No. The tool checks first and hands a file that already fits straight back untouched.
06Will the text still be selectable?
At this size, usually yes. Most files reach 3 MB in the first two stages, which leave text exactly as it was.
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.