Gmail and Outlook attachment limits
Use this when an email bounces with an attachment-too-large error or when the send button greys out before you finish composing.
Use Case
Compress PDF for Email
Email providers reject large attachments automatically. Gmail blocks files over 25MB, Outlook rejects anything above 20MB, and many corporate email systems enforce even lower caps. If your PDF keeps bouncing back, a browser-based compressor is the fastest fix before you hit send.
This page is built for that exact situation: a file that is too large for email and needs to be smaller without losing the content the recipient needs to read.
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When this page helps most
Client and professional document sharing
Contracts, proposals, and reports often exceed email size limits when exported from design or office tools at full quality.
Mobile email workflows
Useful when you are attaching a scanned PDF from your phone and the email app rejects it before sending.
Step-by-step workflow
Step 01
Upload the PDF your email is rejecting
Use the compressor here and upload the file. No signup is required before starting.
Step 02
Compress and check the output size
Download the compressed file and confirm it falls below your email provider's limit. For Gmail, aim under 25MB. For Outlook, under 20MB.
Step 03
Attach the compressed file and send
Use the smaller file as your attachment. If you regularly share large PDFs, keep a compressed version ready before starting the email.
Common issues
The file is still too large for Gmail after compression.
For files over 25MB, Gmail requires Drive sharing instead of a direct attachment. Compress first to get as close to the limit as possible, then use a shared link if it still does not fit.
The compressed PDF looks different from the original.
Check whether the recipient needs print quality or screen quality. For most emails, slightly reduced image quality is acceptable as long as text and tables remain readable.
The corporate email server still rejects the file.
Some corporate mail servers enforce lower limits set by the IT team. Aim for under 10MB and ask the recipient if they know the actual attachment cap.
Keep moving through the right route
Built for real email workflows
What happens to your document between upload and the smaller file you attach to your email.
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No signup required to compress your PDF.
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The workflow works in Chrome, Safari, and other modern mobile browsers.
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Downloaded files are delivered without watermarks.
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Always check the compressed file size before attaching to confirm it meets your email provider's limit.
File retention: Uploaded files are automatically deleted within 1 hour of processing.
FAQ
Frequently Asked Questions
What is Gmail's attachment size limit?
Gmail blocks direct attachments over 25MB and forces you to share via Google Drive instead. Compressing your PDF below 25MB lets you attach it directly without switching to a link.
What is Outlook's attachment size limit?
Outlook enforces a 20MB cap for most accounts. Microsoft 365 accounts may allow higher limits, but the receiving server can impose its own lower cap.
Will compression affect the recipient's ability to print?
Light compression keeps print quality acceptable for most documents. Heavy compression can reduce image clarity. For print-critical files, use the lightest compression that gets you below the size limit.
Can I compress a PDF from my phone before emailing?
Yes. The compressor works in a mobile browser, so you can compress and download the smaller file, then attach it in your email app without any desktop steps.