How to compress a PDF for email (under 25 MB)

Your email client has rejected your PDF because it's too large. This is one of the most common frustrations with PDF files — and one of the easiest to fix. Here's exactly how to compress your PDF to fit within email attachment limits, without losing readability.

Email attachment size limits

Every email provider limits how large an attachment can be. If your PDF exceeds these limits, your email will bounce or the service will ask you to share via a link instead:

Email service	Attachment limit
Gmail	25 MB
Outlook / Hotmail	20 MB
Yahoo Mail	25 MB
Apple Mail (iCloud)	20 MB
ProtonMail	25 MB

Why is my PDF so large?

The most common culprit is embedded images. When you export a presentation from PowerPoint, scan a document, or save a report with high-resolution photos, the PDF embeds those images at full resolution — often 300 DPI or higher.

A single full-page scanned document can be 1–3 MB. A 20-page scan can easily reach 30–60 MB. For screen viewing and email sharing, you only need 72–150 DPI, which dramatically reduces file size.

How to compress your PDF (step by step)

TurboConvert's PDF compressor uses Ghostscript WebAssembly — the same engine as professional tools — running entirely in your browser. Your PDF never leaves your device.

1. Open the Compress PDF tool.
2. Drop your PDF into the upload zone or click to browse.
3. Choose Maximum compression (72 DPI) for the smallest file size.
4. Click Compress PDF and wait a few seconds.
5. Download your compressed PDF and check the file size.
6. If it's still too large, try splitting the PDF into sections using the Split PDF tool and send as multiple emails.

Sending PDF via WhatsApp

WhatsApp allows document attachments up to 100 MB, but very large PDFs load slowly on mobile connections and take up significant storage. For smooth sharing, aim for under 10 MB.

Use the Maximum compression setting (72 DPI) in TurboConvert. This is optimised for screen viewing — exactly what WhatsApp recipients will do. The result typically looks identical to the original when viewed on a phone screen.

Tips for the smallest file size

• Use Maximum compression — 72 DPI is perfectly readable on screen and produces the smallest files. Only use higher quality if the PDF will be printed.
• Don't compress twice. Compressing an already-compressed PDF loses quality without significant size reduction. Start from the original file.
• Split long documents. A 100-page report can be split into sections using the Split PDF tool, then send each section as a separate attachment.
• Convert to images if needed. If someone just needs to read a PDF and you can't get it small enough, use PDF to JPG and send the images instead.
• Use cloud sharing for very large files. If the PDF is above 50 MB even after compression, use Google Drive or WeTransfer and share a link — this bypasses email limits entirely.