Best PDF Format for Email

Before talking about PDF settings, know your email size limit. Gmail and Outlook.com allow attachments up to 25 MB. Corporate Exchange servers often limit attachments to 10 MB or even 5 MB. iCloud Mail allows up to 20 MB. Yahoo Mail allows 25 MB.

If your PDF is over these limits, the email will bounce. Some providers return an error message; others silently fail. To avoid problems, aim to keep PDF attachments under 20 MB — that gives you a safety margin and works for every major email provider.

For files over 25 MB, the best practice is to upload the PDF to a file-hosting service (Google Drive, Dropbox, OneDrive, WeTransfer) and include a download link in the email body. This avoids the attachment size limit entirely and lets you track downloads.

For most email use cases, the Recommended compression level (about 65% image quality, 150 DPI) is ideal. It produces files that are 70–90% smaller than the original PDF, with no visible quality loss on screen. Text remains sharp and selectable; images look fine for screen viewing.

Use Strong compression only when you absolutely must hit a tight size limit. Strong compression reduces image quality to about 40% and DPI to 100, which makes photographs visibly softer but produces very small files. For text-only documents, Strong compression has no downside — there's no image data to degrade.

Use Light compression when image quality is critical and file size is less important. Light compression preserves 80%+ of original image quality, suitable for design portfolios, marketing materials, or documents that will be printed.

If your recipients are mostly in North America, use Letter page size (8.5 × 11 inches). If they're in Europe, Asia, or most of the rest of the world, use A4 (210 × 297 mm). If you're not sure, A4 is the safer default — it's the international standard (ISO 216) and works fine on Letter-size paper with minor scaling.

Most PDF creation tools let you choose page size in the export settings. If you're starting from a Word document, set the page size in Word before exporting to PDF; the PDF will inherit the Word page size.

Mixed page sizes within the same PDF work fine for screen viewing, but cause printing problems if the recipient prints the document. For printable PDFs, stick with one page size throughout.

Embedding fonts ensures the PDF looks identical on every device, regardless of which fonts are installed. This is the safe default — embed all fonts unless you have a specific reason not to.

The downside of font embedding is file size. Each embedded font adds 100–500 KB. For a document using five fonts, that's 0.5–2.5 MB of font data, which can push a borderline PDF over the email size limit.

Font subsetting is the compromise: instead of embedding the entire font, only the specific characters used in the document are embedded. A document that uses the word 'Hello' in a particular font embeds only the letters H, e, l, and o — typically a few kilobytes instead of hundreds. Most PDF creation tools support subsetting; check the export options.

PDF/A is a special variant of PDF designed for long-term archival. It embeds all fonts, restricts features that might not be supported in future PDF readers, and is required by some government and legal organizations for records retention.

For everyday email use, you don't need PDF/A. Standard PDF works fine for contracts, reports, and any document that will be read and discarded within a few years. PDF/A produces slightly larger files because of the font embedding requirements.

Use PDF/A only when the recipient specifically requests it (some legal workflows require it) or when you're archiving a document for long-term storage. Most email recipients won't notice or care whether you send PDF or PDF/A.