Why does Gmail cap attachments at 25 MB? Can I override it?

Historical artefact — the 25 MB cap dates from when email infrastructure had tight per-message limits and most ISPs / corporate relays enforced a similar cap. Gmail does not allow individual users to override the cap; the implicit alternative is Google Drive share-links (Gmail offers this automatically when you attach a 25MB+ file). Outlook is similar at 20 MB for outlook.com / 33 MB for some Microsoft 365 plans; corporate Exchange caps are policy-set by the admin and may be lower or higher. The good news: there are five well-tested workarounds, ordered from "do this first" to "last resort".

What is the right order of remedies for a too-big PDF?

(1) Compress the PDF first — typically halves or thirds the size for photo-heavy files. Often gets you under the cap without anything else. (2) If still too big and the PDF has natural document boundaries, split into smaller files and email as multiple messages. (3) If splitting is not appropriate (single signed document, contiguous report), use the email provider's built-in share-link feature (Gmail → Drive link, Outlook → OneDrive link). (4) If you do not want the recipient on your cloud, use a transfer service (WeTransfer, Smash, Bitwarden Send) — the file is uploaded once, the recipient downloads via a link, the file expires after a configurable period. (5) If none of the above works (recipient blocks external services), rehost on a server you control and email the link.

Will compression actually get me under 25 MB?

Almost always, for typical PDFs. A 30 MB photo-heavy PDF compresses to ~10–15 MB on the Medium preset; a 50 MB scanned book to ~15–25 MB. The exceptions: PDFs that are already aggressively compressed (output from a previous compression pass), and very long scanned documents where every page is a high-res image. For those, splitting is the safer answer.

Is the Drive / OneDrive share-link option safe to use for sensitive PDFs?

Depends on the permissions you set. By default Gmail-via-Drive shares the file with "anyone with the link" — bad for sensitive content. Set the link to "specific people" (the recipient's email) and the file requires sign-in to access; the file is no more exposed than a normal Drive share. OneDrive offers the same option. For the most-sensitive content (legal, medical, financial documents to recipients you do not fully trust), a transfer service with a download-expiry deadline + password is a better fit than Drive sharing.

WeTransfer / Smash / etc. — are these reliable?

Yes, with caveats. WeTransfer free tier handles files up to 2 GB and is widely accepted by recipients. Smash has no file-size limit on free tier (impressive). Bitwarden Send is encrypted end-to-end with a destruction deadline. Caveats: (a) corporate networks often block transfer-service domains as data-exfiltration risk; if your recipient is corporate, check whether their IT allows these domains before sending. (b) Transfer services upload to their cloud — for highly sensitive content, prefer end-to-end-encrypted options (Bitwarden Send, Mozilla Send) over plain transfer services.

Is my PDF uploaded to your servers when I use the compress / split tool?

No. Both compress and split run entirely in your browser. The PDF is loaded into a sandboxed memory buffer, processed locally, and the result is delivered as a download. Verify in DevTools Network — zero outbound requests during compression or splitting. The point of using a browser-side tool to prep the file for emailing: the file does not transit a third-party cloud before being attached to your email.

How do I make sure the recipient can open the file at the other end?

Three reliability checks. (a) Use a standard PDF version (1.4–1.7); avoid PDF 2.0 features that older Acrobat versions may reject. (b) Embed fonts via the font-embedding checker before sending; non-embedded fonts will substitute on the recipient's system. (c) Test-open the compressed / split files in at least two readers (Acrobat + Preview, or Acrobat + Chrome built-in) before sending. The 30 seconds spent verifying saves an hour of "did you get the file?" back-and-forth.

How to Send Large PDFs by Email (Past Gmail's 25MB)

6 min read

How to send large PDF files via email — workarounds for the 25 MB Gmail limit

By ScoutMyTool Editorial Team · Last updated: 2026-05-20

After working with hundreds of users on document delivery cases, the "your file is too big to send" warning has not aged out as a problem because documents have gotten bigger (high-res scans, photo- heavy reports) while the major email providers have kept their 25 MB cap. The good news: there are five reliable ways around the cap, with different trade-offs depending on whether the recipient is on the same cloud, whether the file is sensitive, and whether you can split it. Below is the ordered playbook.

Email attachment caps by provider

Provider	Attachment cap
Gmail (free, Workspace standard)	25 MB
Outlook.com (free)	20 MB
Microsoft 365 (per admin policy)	20–150 MB
Apple iCloud Mail	20 MB (Mail Drop extends to 5 GB)
Yahoo Mail	25 MB
Proton Mail (free)	25 MB
Corporate Exchange (typical)	10–50 MB (policy-set)

Caps verified as of May 2026 from each provider's public help docs.

The five workarounds, ordered from first-to-try to last-resort

Compress the PDF. Open in Compress PDF with the Medium preset. Halves or thirds the size for photo-heavy files; less effective on text-only. If the result is under 25 MB, you are done.
Split the PDF. If compression alone is not enough and the document has natural boundaries (chapters, sections, photos), split via Split PDF into under-25-MB pieces. Email as multiple messages, labelled "Part 1 of 3, Part 2 of 3..." Useful for archival packets, photo collections, multi-chapter books.
Use the built-in share-link. Gmail auto-prompts a Drive link when you attach a 25 MB+ file; Outlook does the same with OneDrive. The recipient gets a link rather than an attachment. Set permission to "specific people" rather than "anyone with the link" for sensitive content.
Use a transfer service. WeTransfer (free tier 2 GB), Smash (no size cap on free), Mozilla Send and Bitwarden Send (end-to-end encrypted with expiry). Upload, get a link, send the link via email. The trade-off: the file transits a third- party cloud, so end-to-end-encrypted services are preferable for sensitive content.
Rehost on a server you control.Last resort when recipient blocks transfer services and Drive sharing is not viable (different cloud providers, corporate firewall). Upload to a server you own; email the URL. Use a temporary URL with expiry; do not leave files at predictable URLs.

Choosing between workarounds — quick guide

One-off, non-sensitive file: compress. Saves the recipient the click-through; keeps the workflow inside email.
Multi-doc bundle (signed contracts, photo batch): split + email parts. The recipient gets a coherent set of attachments.
You both use the same cloud (Drive / OneDrive): share-link. Native UX, no transfer-service round-trip.
Cross-cloud, sensitive content: encrypted transfer service. Bitwarden Send or similar with expiry.
Recipient blocks everything: rehost. The fallback for the most-locked-down corporate firewalls.

Frequently asked questions

Why does Gmail cap attachments at 25 MB? Can I override it?: Historical artefact — the 25 MB cap dates from when email infrastructure had tight per-message limits and most ISPs / corporate relays enforced a similar cap. Gmail does not allow individual users to override the cap; the implicit alternative is Google Drive share-links (Gmail offers this automatically when you attach a 25MB+ file). Outlook is similar at 20 MB for outlook.com / 33 MB for some Microsoft 365 plans; corporate Exchange caps are policy-set by the admin and may be lower or higher. The good news: there are five well-tested workarounds, ordered from "do this first" to "last resort".
What is the right order of remedies for a too-big PDF?: (1) Compress the PDF first — typically halves or thirds the size for photo-heavy files. Often gets you under the cap without anything else. (2) If still too big and the PDF has natural document boundaries, split into smaller files and email as multiple messages. (3) If splitting is not appropriate (single signed document, contiguous report), use the email provider's built-in share-link feature (Gmail → Drive link, Outlook → OneDrive link). (4) If you do not want the recipient on your cloud, use a transfer service (WeTransfer, Smash, Bitwarden Send) — the file is uploaded once, the recipient downloads via a link, the file expires after a configurable period. (5) If none of the above works (recipient blocks external services), rehost on a server you control and email the link.
Will compression actually get me under 25 MB?: Almost always, for typical PDFs. A 30 MB photo-heavy PDF compresses to ~10–15 MB on the Medium preset; a 50 MB scanned book to ~15–25 MB. The exceptions: PDFs that are already aggressively compressed (output from a previous compression pass), and very long scanned documents where every page is a high-res image. For those, splitting is the safer answer.
Is the Drive / OneDrive share-link option safe to use for sensitive PDFs?: Depends on the permissions you set. By default Gmail-via-Drive shares the file with "anyone with the link" — bad for sensitive content. Set the link to "specific people" (the recipient's email) and the file requires sign-in to access; the file is no more exposed than a normal Drive share. OneDrive offers the same option. For the most-sensitive content (legal, medical, financial documents to recipients you do not fully trust), a transfer service with a download-expiry deadline + password is a better fit than Drive sharing.
WeTransfer / Smash / etc. — are these reliable?: Yes, with caveats. WeTransfer free tier handles files up to 2 GB and is widely accepted by recipients. Smash has no file-size limit on free tier (impressive). Bitwarden Send is encrypted end-to-end with a destruction deadline. Caveats: (a) corporate networks often block transfer-service domains as data-exfiltration risk; if your recipient is corporate, check whether their IT allows these domains before sending. (b) Transfer services upload to their cloud — for highly sensitive content, prefer end-to-end-encrypted options (Bitwarden Send, Mozilla Send) over plain transfer services.
Is my PDF uploaded to your servers when I use the compress / split tool?: No. Both compress and split run entirely in your browser. The PDF is loaded into a sandboxed memory buffer, processed locally, and the result is delivered as a download. Verify in DevTools Network — zero outbound requests during compression or splitting. The point of using a browser-side tool to prep the file for emailing: the file does not transit a third-party cloud before being attached to your email.
How do I make sure the recipient can open the file at the other end?: Three reliability checks. (a) Use a standard PDF version (1.4–1.7); avoid PDF 2.0 features that older Acrobat versions may reject. (b) Embed fonts via the font-embedding checker before sending; non-embedded fonts will substitute on the recipient's system. (c) Test-open the compressed / split files in at least two readers (Acrobat + Preview, or Acrobat + Chrome built-in) before sending. The 30 seconds spent verifying saves an hour of "did you get the file?" back-and-forth.

Shrink your PDF for email now — free, no signup, no upload

Five compression techniques, target-size mode, splits for over-cap files. Runs entirely in your browser.

Open the Compress PDF tool at scoutmytool.com/pdf/compress-pdf →