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.
Drop files here or browse
Supports JPG, PNG, WebP, GIF, PDF - up to 20 files, 50 MB each
Compress by
Each file is compressed to fit under this size. Popular targets: 5 MB, 2 MB, 1 MB.
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.
Which tool for which attachment
| You're attaching | Use | Why |
|---|---|---|
| Photo or scanned page (JPG/PNG) | Compress here, target ~22MB | A single photo almost never needs the full budget — this matters more when several images are attached to the same email. |
| A PDF report or contract | Compress here (PDF included in "all") | Text-based PDFs usually clear 25MB with lossless optimization; only scanned, image-heavy PDFs need aggressive rasterization. |
| A short video clip | Video compressor, target ~22MB | Gmail silently offers a Drive link instead of a direct attachment once you're near or over 25MB — compressing avoids that extra step for the recipient. |
| Multiple files for one email | ZIP compressor, target ~22MB | One compressed archive is simpler for a recipient than several separate attachments, and lets the tool balance the budget across all of them. |
Known limits
The 25MB figure is what Gmail enforces on its own send path, but a message can still bounce if the recipient's mail server has a lower cap of its own — some corporate email systems restrict incoming attachments to 10-15MB regardless of what Gmail allows outbound. If a compressed file still bounces, that's usually the recipient's limit, not yours, and a smaller target or a cloud link is the fallback.
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.
Why does Gmail cap attachments at 25MB when Drive files can be huge?
25MB is a limit on the email protocol path itself, not Drive — attachments are base64-encoded into the message body, which inflates their size by roughly a third, and mail servers along the way (yours and the recipient's) enforce their own caps. Past 25MB, Gmail switches to inserting a Drive link automatically rather than attempting to deliver the raw file.
Does compressing my attachment here send it to Google or anyone else first?
No. Compression happens before you ever open Gmail — the file never touches this site's infrastructure (there isn't any to touch) and obviously isn't sent to Google until you actually attach it and hit send yourself. Everything above runs as a browser-local operation using the Canvas API, pdf-lib, ffmpeg.wasm, or libarchive-wasm depending on file type.
Learn more
From the blog
How to compress a video for email
Attachments and email have never mixed well with video — here is the fix.