Email & portal file size limits, in one table.
The numbers portals print in bold — Gmail, Outlook, job forms, and government uploads — plus the exact PdfPixels workflow that makes a file fit.
25 MB
Gmail per message
~20 MB
Outlook.com
100 KB
Strictest portals
The limits table
Figures below are the commonly documented caps as of 2026. Providers and form owners change rules, so treat the portal’s own error message as final — and leave headroom (target ~80% of any stated cap).
| Destination | Typical cap | What fits |
|---|---|---|
| Gmail (per message) | 25 MB total | Most compressed PDFs; aim under ~20 MB |
| Outlook.com | ~20 MB | Corporate tenants often lower (~10 MB) |
| Job / admissions portals | 1–5 MB common | Compressed PDFs, 100–500 KB photos |
| Government / visa forms | 100 KB–1 MB strict tiers | Single-page PDFs, exact-KB photos |
Shrink-to-fit workflows
- PDF too big to email? Run Compress PDF (up to 50 MB). Still over? Split PDF out unneeded pages first — fewer pages beats harsher compression.
- Portal demands 100–500 KB? Use the exact-target tools: 100KB, 200KB, 500KB, or under 1MB. Grayscale first via Grayscale PDF for color scans that will not fit.
- Photo rejected by a form? Compress Image to the exact KB number, or Increase Image Size if the portal enforces a minimum. Match dimensions too with Resize Image.
- Many photos to send? Budget per message, not per photo: ten 2 MB photos fit Gmail; thirty do not. Compress to a few hundred KB each or share an album link.
Frequently asked questions
What is the Gmail attachment size limit?
Gmail allows up to 25 MB per message including attachments. Stay under ~20 MB in practice so encoding overhead does not push you over. Larger files must go through Google Drive links.
What is the Outlook attachment size limit?
Outlook.com allows roughly 20 MB per message. Corporate Microsoft 365 tenants are often stricter (commonly 10 MB) because admins lower the default. Check your organization’s bounce message for the exact cap.
Why do job and government portals reject my PDF even though it sent fine by email?
Email caps (20–25 MB) are far roomier than form upload caps, which commonly sit at 1–5 MB and sometimes at strict 100–500 KB tiers. A PDF that emails fine can still be 10× over a portal limit.
How small can a readable PDF get?
A 1–3 page text PDF can live under 300 KB comfortably. Single-page forms can reach 100 KB. Multi-page color scans realistically bottom out around 500 KB–1 MB before text suffers — split pages first, then compress.