Which compression level should I use for email attachments?

Medium compression is best for most email use cases — it keeps document text razor-sharp while reducing file size by around 80%. Use High compression only when you need to meet a strict size limit such as under 500KB.

What are the email attachment size limits?

Gmail allows 25MB, Outlook and Hotmail allow 20MB, Yahoo Mail allows 25MB, and Apple Mail allows 20MB. Corporate email servers often limit attachments to 10MB or less. Keeping PDFs under 1MB ensures reliable delivery on all providers.

Compress PDF for Email — Reduce PDF Attachment Size

Large PDF attachments can be rejected by email servers, bounce back, or take forever to send on mobile. Our free PDF compressor reduces PDF file size by up to 90% — so your attachments send instantly and reliably on Gmail, Outlook, Yahoo Mail, and any email client.

Compress your PDF for email in seconds — free, private, no account needed.

Compress PDF for Email

How to compress a PDF for email

Go to compressfiles.online on your phone or computer
Upload your PDF attachment
Choose Medium compression (best quality-to-size ratio for documents)
Click Compress PDF and wait a few seconds
Download the compressed file and attach it to your email

Email attachment size limits by provider

Gmail — 25MB per email, but large attachments convert to Google Drive links
Outlook / Hotmail — 20MB per email; corporate Outlook may be as low as 10MB
Yahoo Mail — 25MB per email
Apple Mail (iCloud) — 20MB; larger files use Mail Drop
Corporate email servers — Often 10MB or less; some legacy servers cap at 2–5MB

Even within the technical limits, smaller attachments load faster for the recipient — especially on mobile. Keeping PDFs under 1MB is a best practice for professional communication.

Which compression level should I use for emails?

Medium — Best for most email use cases. Keeps document text razor-sharp while reducing file size by ~80%. Ideal for reports, invoices, contracts, and CVs.
High — Best when you need to meet a strict size limit (e.g., under 500KB). Some image quality is sacrificed but text remains fully readable.
Low — Near-original quality with modest reduction. Use when the recipient will print the document and quality matters most.

Is the compressed PDF safe to email?

Yes. Files are processed in memory on a secure server and deleted immediately after download. The PDF is not stored, logged, or accessible by anyone other than you. Compressed PDFs open normally in all email clients and PDF readers.

Ready to compress your PDF attachment?

Compress PDF Free

Compress PDF for Email — Reduce PDF Attachment Size

How to compress a PDF for email

Email attachment size limits by provider

Which compression level should I use for emails?

Is the compressed PDF safe to email?

Related guides