Compress PDF for Email Attachment Limits
Choose Gmail 25MB, Outlook 20MB, Outlook.com 25MB, or set any size. PDFThin optimizes first (no visible changes when possible). If it still won't fit, we split your PDF into attachment-ready parts automatically.
How it works
Upload
Drag and drop your PDF or pick a file.
We process
Optimize and split when needed.
Download
Grab a single PDF or a zip of parts.
Email-ready results
Fit-or-split result
Get one PDF that fits, or a ZIP of parts under the limit.
Email presets
Gmail 25MB, Outlook 20MB, Outlook.com 25MB, plus custom size.
Private by default
Files auto-delete after 60 hours; we don't store document contents in logs.
FAQ
What is Gmail's attachment limit?
Gmail supports up to 25 MB of attachments per email. If it's larger, Gmail sends a Google Drive link instead. See compress PDF to 25MB.
Why does a 24 MB PDF sometimes fail to send?
Some mail systems encode attachments (Base64/MIME), which can increase message size. If you hit errors, set a slightly lower custom target (e.g., 18-20 MB) or split by size.
What's Outlook's attachment limit?
Outlook often has a 20 MB limit for internet email accounts. Outlook.com supports 25 MB for file attachments. Use the 20 MB preset if you run into send errors.
What happens if one page is too large?
We will tell you a single page exceeds the limit and suggest a higher limit or quality mode.
Do you support encrypted PDFs?
No. Encrypted PDFs are not supported.
How long are files stored?
Files auto-delete after 60 hours.
Why PDFThin for email PDFs
Email-safe PDF compression
Reduce file size while keeping layout intact. PDFThin optimizes structure, fonts, and images for reliable delivery.
Split by size, not by chance
If optimization is not enough, we split into parts that stay under your limit and preserve page order.
Email limits and quick links
Use compress PDF to 25MB for Gmail or compress PDF to 20MB for Outlook.
If one file still will not fit, switch to split by size. For details, read the complete email compression guide.
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Step-by-step workflow for Gmail 25MB and Outlook 20MB limits.
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