Compress Files for Gmail
Gmail caps attachments at 25 MB per email — and because of encoding overhead the real ceiling is closer to 18 MB. Pick what you're attaching below and the right tool opens with a 25 MB target already set. Everything happens in your browser, so nothing is uploaded.
Compress a video
MP4, MOV, WebM — the usual reason an upload is too big.
Targets 25 MB →
Compress an image
JPG, PNG, WebP or HEIC down to an exact size.
Targets 25 MB →
Compress a PDF
Shrink scanned docs, slide decks and reports.
Targets 25 MB →
Compress a ZIP / lots of files
Recompress every image and PDF inside an archive to fit.
Targets 25 MB →
Gmail attachment limits
| Direction | Limit | Notes |
|---|---|---|
| Sending | 25 MB | Total size of all attachments on one email. |
| Receiving | 50 MB | Gmail accepts incoming mail up to 50 MB. |
| Reliable in practice | ~18 MB | Encoding adds ~33% overhead, so aim under. |
Go over 25 MB and Gmail swaps your attachment for a Google Drive link automatically. Compressing under the limit keeps the file attached directly to the email, which recipients can open without extra clicks or sign-ins.
Tips for emailing large files
- • PDFs are the usual offender. Scanned documents and slide decks compress a lot — start there.
- • Aim for ~18 MB, not 25. That leaves room for the encoding overhead Gmail adds.
- • Multiple attachments? Remember the 25 MB is the combined total. Zip and recompress them together.
- • Genuinely huge file? A Google Drive link is fine — but a compressed direct attachment is friendlier.
Frequently asked questions
What is Gmail's attachment size limit?
Gmail lets you send up to 25 MB of attachments per email and receive up to 50 MB. The 25 MB is the combined size of every file on the message, not per file.
Why does a 23 MB file fail to attach in Gmail?
Email encoding (base64) inflates attachments by roughly a third before they are sent, so a file that is 20 MB on disk can cross the 25 MB ceiling once Gmail packages it. Aim for about 18 MB or less to stay safely under the limit.
What happens if my file is over 25 MB?
Gmail automatically uploads it to Google Drive and inserts a share link instead of attaching the file. Compressing below 25 MB lets you attach it directly, which recipients usually prefer.
Are my files uploaded to a server?
No. Compression runs entirely in your browser — nothing is uploaded and your files never leave your device.