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"The attachment is too large" is one of the most common email errors. The fix is to compress your PDF so it fits under the limit. Here are the real size limits you are hitting, and how to shrink a PDF to the exact target — free, and without uploading your file anywhere.
Open Compress PDF →Different mail providers cap attachment size. These are the common limits to aim under:
| Email service | Attachment limit |
|---|---|
| Gmail | 25 MB |
| Outlook.com / Hotmail | ~20–25 MB |
| Yahoo Mail | 25 MB |
| Many company / work servers | 10 MB (sometimes 5 MB) |
Note: these are the sending limits. The recipient's server may be stricter, so aiming for under 10 MB is the safest bet for reaching anyone.
Most PDFs fit easily. The recommended level is usually more than enough — you rarely need to compress hard for a 25 MB limit.
Apply the recommended level. If the file is image-heavy and still too big, move up one level, or split off pages you do not need to send.
Use a stronger compression level. For scanned documents, also consider whether every page is needed — removing extra pages with Remove Pages is often the quickest way to get under 5 MB.
Privacy note: ACS PDF compresses your PDF in your browser — the file is never uploaded to a server. That matters when the PDF is an invoice, statement or contract. Learn why no-upload is safer →
Gmail and Yahoo allow up to 25 MB, and Outlook.com about 20–25 MB. Many work servers cap attachments at 10 MB or even 5 MB, so a smaller file is safer.
Open the Compress PDF tool, add your file and apply the recommended level. If it is still over 10 MB, remove pages you do not need or use a stronger level to hit the target.
The recommended level keeps pages clearly readable. Only very strong compression noticeably lowers image quality, so start light and increase only if you must hit a strict limit.