Gmail Attachment Size Limit & How to Send Larger Files
Google Gmail rejects any email message exceeding 25 megabytes in total MIME size. Because binary attachments require Base64 encoding (which adds 33 % overhead), files larger than approximately 18.5 MB will fail to send.
Up to 500 files or folders · Client-side AES-256-GCM encryption · Zero accounts required
Ücretsiz Transfer BaşlatGmail (Google) limit breakdown
| Constraint | Details |
|---|---|
| Stated attachment limit | 25 MB (entire message, headers + body + files) |
| Encoding overhead | Base64 encoding increases file size by 33% |
| Cloud fallback behavior | Forces Google Drive upload (requires recipient to have Google access) |
| Recipient requirement | Recipient email server must also accept 25 MB |
| Privacy & scanning | Stored in plaintext on Google servers; scanned for advertising & spam |
Why files bounce on Gmail (Google)
When you attach a file in Gmail, your browser translates raw binary bytes into ASCII text (Base64). A 20 MB MP4 or PDF becomes a 26.6 MB payload. Gmail checks the encoded message size against its 25 MB ceiling and rejects the delivery or forces you to upload it to Google Drive.
How to send files larger than 25 MB
- Do not send the raw file as an email attachment — send an encrypted LimeShare link instead.
- LimeShare encrypts files up to 3 GB in your browser with AES-256-GCM before upload.
- Your recipient gets full-speed download without needing a Google account or requesting drive permissions.
- The link automatically self-destructs after 48 hours or upon first download.
Frequently asked questions
What is Gmail's exact attachment limit in 2026?
Gmail allows a maximum message size of 25 MB for sending and 50 MB for receiving. However, because attachments are Base64 encoded, any single file larger than ~18.5 MB will trigger Gmail's Google Drive prompt.
Why is Google Drive not ideal for sending confidential files?
Google Drive retains your files indefinitely, indexes plaintext content, and often prompts recipients for Google login or permission requests. LimeShare provides zero-knowledge encryption and auto-purging.