Attachment limits: Gmail & Outlook

You hit attach — and your email bounces. Or it sends but the recipient's server rejects it. Attachment limits trip up professionals every day because every provider caps message size, and those caps are smaller than most decks, video snippets, or raw exports.

Here's how Gmail and Outlook handle limits in practice, how to work around them cleanly, and a few things most guides don't mention.

The limits you'll actually hit

Gmail allows attachments up to 25 MB per message. That sounds generous until you're dealing with raw exports, layered design files, or any video at all. Gmail automatically offers to upload to Google Drive and insert a link when you hit the ceiling — which is the right behaviour, but you should understand why before you rely on it.

Outlook.com and Microsoft 365 personal typically sits around 20 MB. Exchange/365 organizational accounts are often configured differently by IT — some allow 34 MB, some less. The weakest link wins: your outgoing server might accept a 30 MB file that the recipient's server silently drops.

File types that blow up unexpectedly: Raw photos from modern cameras (30–50 MB each), uncompressed audio, PSDs and AI design files, Excel with embedded images, and video files of any kind. PDFs with embedded high-res images also balloon — a 40-slide deck with full-bleed photography can easily exceed 25 MB.

The cloud link workflow (should be your default)

For anything over ~10 MB, stop attaching and start linking:

1. Upload to Google Drive, OneDrive, Dropbox, or your company's approved storage.
2. Generate a share link — view-only for external recipients unless they need to edit.
3. Paste the link with one sentence of context: what it is, why it matters, and if it expires.

This has real advantages beyond beating size limits: the recipient gets the latest version if you update the file, you can revoke access after a project ends, and it doesn't inflate their inbox storage. For sensitive documents, some platforms let you set a link expiry or require sign-in before viewing.

For truly large files (recordings, raw footage, large data exports) where cloud storage is awkward, services like WeTransfer or Filemail generate temporary download links — convenient for one-off sends to external contacts.

When you genuinely need to attach (not link)

Some workflows require actual attachments — automated systems that parse PDFs, contract review platforms, regulatory submissions. In those cases:

Compress images before embedding in documents. Export presentations as "compressed" PDFs, not "best quality." On Mac, Preview's Export function offers size reduction. On Windows, many PDF tools include compression on save.

ZIP sparingly. Zipped files can trigger spam filters — security tools are suspicious of archives, especially password-protected ones. If a recipient's IT blocks ZIPs, your email disappears silently.

Mobile considerations

Sending from a phone adds another wrinkle — mobile email apps sometimes re-compress images automatically and sometimes don't, depending on client settings. If you need consistent behavior, send from a desktop where you can verify what's actually being attached.

Professional etiquette

Name files like adults: Acme-Q3-Proposal-v3.pdf, not final_FINAL_v2_use_this_one.pdf. Mention size for heavy downloads: "The video walkthrough is ≈120 MB — Wi-Fi recommended." That one line saves the recipient frustration and signals you've thought about them.

Finding old attachments later

Once you adopt the cloud link habit, retrieving old files means going to your cloud storage — not digging through email. But when you do need to find an old attachment that was emailed directly, search operators make it fast: has:attachment from:sarah filename:pdf in Gmail or Faraday narrows thousands of emails to a handful instantly. Faraday supports the full operator vocabulary plus contextual search — "proposal from the Acme thread Q1" finds it even if the subject said something else.

Attachment limits are a small forcing function toward a better habit. Share links instead of files, compress when you must attach, and keep a cloud storage folder organized by project. Your email and your recipients will both be lighter for it.