Guide · 3 min read · Updated 8 October 2026
How to make a PDF smaller for email and upload forms
Gmail stops at 25 MB per attachment, and many bank, university and government upload forms accept only a few megabytes. A PDF that was easy to make — a few phone photos, a scan of a contract — is often far bigger than that. Here is why it happens, and how to shrink the file without making it unreadable.
Why some PDFs are huge
Text is tiny: a page of typed text takes a few kilobytes. Pictures are what make a PDF big. A single phone photo is often 3–8 MB, and a scanner may save every page as a full-colour image at 300 DPI or more. Ten photos in one PDF easily reach 50 MB, while a 50-page report without pictures can stay under 1 MB.
So the first question is what kind of PDF you have:
- Mostly text (contracts, reports exported from Word): already compact, so it won’t shrink much.
- Photos or scans (a stack of phone pictures, a scanned passport, a signed paper): this is where compression helps most — often 50–90% smaller.
Shrink it with Compress PDF
- Open Compress PDF and add one or more PDF files.
- Choose Balanced or Strong (the next section explains the difference).
- Press Start and compare the sizes shown for each file.
- Download the smaller PDFs.
The work happens in your browser, so contracts, IDs and medical papers are never uploaded anywhere.
Balanced or Strong?
| Balanced | Strong | |
|---|---|---|
| What it does | Recompresses the photos inside the PDF | Turns every page into an optimised image |
| Text | Stays selectable and searchable | Becomes part of the picture, so it can’t be selected |
| Best for | Reports, contracts, anything with real text | Scans and photo-heavy files where size matters most |
| Result | Smaller; depends on how many photos there are | The smallest |
Try Balanced first. If the file is still too big, start again from the original with Strong. Always keep the original file.
If it is still too big
- Split it. Cut the PDF into two or three parts with Split PDF and send them in separate emails or uploads.
- Remove pages you don’t need. Use reorder and delete pages before compressing — every page you drop is size you don’t have to squeeze out.
- Shrink the photos first. If you build the PDF from pictures, reduce them with Compress image and then combine them with JPG to PDF. Smaller pictures in means a smaller PDF out.
- Combine after compressing. If you need one file from several, compress each part and then join them with Merge PDF.
Check the result before you send it
Open the compressed file at 100% zoom and look at the small print, stamps, signatures and numbers. If something has turned blurry, go back to Balanced or send the original in parts. If a PDF can’t get any smaller, Toola keeps your original instead of handing you a bigger file.
Why not use any online compressor?
Most online compressors upload your file to a server and promise to delete it later. For a contract, a bank statement or a scanned ID that is a risk you don’t need to take. Toola compresses in your browser, so the document never leaves your device.
Frequently asked questions
What is the email attachment limit?
Gmail allows up to 25 MB per message, and other providers differ. Upload forms are often stricter, from 1 MB to 10 MB — check the limit shown on the form.
Will compression make my text blurry?
Not in Balanced mode, which keeps real text sharp and selectable. Strong mode turns pages into pictures, so check small print after using it.
Why didn’t my PDF get smaller?
A PDF that is mostly text is already compact, and one that was compressed before may have little left to give. Try Strong if it is a scan, or split the file.
Can I compress several PDFs at once?
Yes. Add as many files as you like and download the results one by one.