Compress a Video for Email: The Number to Type for Gmail, Outlook and iCloud

Four limits, from each provider's help

We read the help pages of four mail services on October 22, 2026, without signing in. Gmail: “For personal Gmail accounts, the limit is 25 MB.” Yahoo Mail: the attached files in one message “must not exceed 25MB in total file size.” Apple gives iCloud Mail messages a limit of 20 MB, or up to 5 GB with Mail Drop turned on.

Microsoft gives Outlook.com two figures. Its Outlook help on attachment size gives 20 megabytes for accounts such as Outlook.com. That limit “includes both the size of the attachment and the size of the email.” A known-issues page, last updated in November 2023, says 25 MB. We plan for 20. On a work or school account, the administrator sets the limit.

Past its limit, Gmail does not attach the file. It “automatically removes the attachment and adds it as a Google Drive link in the email.” Apple Mail asks to send it with Mail Drop instead. Either way, the video arrives as a link, not as an attachment. The same limits for documents are on Compress PDF for Email.

Mail makes the file over a third bigger

An attachment does not travel as the file you picked. Mail carries it as base64 text. RFC 2045, the standard that defines it, turns every 3 bytes into 4 characters and keeps lines to 76 characters at most. With a line break after each line, the file grows by 36.8 percent. Our script turned a video of 16,804,180 bytes into 22,995,198 bytes of base64.

Whether a limit counts the file or this larger copy, most of the help pages do not say. Gmail's does not, and Yahoo's speaks of “total file size”. Microsoft's documentation for its business mail, Exchange Online, does count the growth. Messages that leave its datacenters get “an additional 33% translation encoding increase”. For that reason, Outlook on the web lets those accounts send 25 percent less than the set limit.

So every limit has two safe numbers: one for a service that counts the file, and one for a service that counts the mail.

The megabyte in the target size field

Compress Video counts a megabyte as 1,048,576 bytes, in the field “Or a target size” and in the sizes it shows. Type 24, and it aims at 25,165,824 bytes. It encodes the video, weighs it and corrects the bitrate for up to three passes. It stops once the file lands between 88 and 100 percent of that number, or after the third pass.

On October 22, 2026, a target of 24 gave our 30-second clip 23,738,856 bytes, and the page showed 23 MB. A target of 17 gave 16,804,180 bytes, shown as 16 MB. Counted in millions of bytes, the two files are 23.7 and 16.8.

None of the four help pages says which megabyte it means. The numbers below fit under either count.

The number to type for each service

For Gmail and Yahoo Mail, type 23 if the service counts the file. The result can then be at most 24,117,248 bytes. Type 17 if it counts the mail: at most 17,825,792 bytes, which is 24.4 million once encoded. On our clip, 23 gave 22,787,571 bytes and 17 gave 16,804,180.

For Outlook.com and iCloud Mail, type 19 if the file is counted, for at most 19.9 million bytes. Type 13 if the mail is counted, for at most 18.7 million once encoded. Microsoft also counts the text of the email, and 13 leaves room for it. On our clip, 19 gave 18,753,852 bytes and 13 gave 12,790,137.

Why not 18 and 14? At 18, our clip came out at 17,784,709 bytes, 24.3 million encoded, so it fit. But the page may land anywhere up to 18,874,368 bytes, and that encodes to 25.8 million. The ceiling of 14 encodes to 20.1 million.

When you cannot tell how a service counts, use 17 or 13. A file that fits the mail also fits the file count.

What is left of the picture

Our test clip is 30 seconds of 1080p at 30 frames per second, 48,640,698 bytes. It shows a moving fractal pattern, a moving test chart and film grain. Four copies joined made a two-minute clip of 194,579,319 bytes. Ten copies, encoded again at 4.9 Mbps to stay under the page's 200 MB limit, made a five-minute clip of 188,771,177 bytes.

We scored every result against its source with VMAF, a video quality score from 0 to 100 where higher means closer to the source. Film grain is the hardest thing to keep, so read the scores as a comparison between settings, not as a grade.

At 1080p, the 30-second clip scored 66.2 at a target of 24, 64.8 at 17 and 63.3 at 13. Each took about five seconds, in headless Chrome on a 2023 Mac laptop. On a clip this short, going down to 13 costs little.

At two minutes, 1080p runs short of bits. At 17, the page kept 1920 × 1080 at about 1 Mbps and scored 46.5. At 13, the page said after three passes and 53 seconds that it could not reach the target. It handed over 14,932,533 bytes, 20.4 million encoded, which is over a 20 MB mail count. With Resolution set to 720p, 17 scored 58.3 and 13 gave 12,530,368 bytes in 11 seconds, scoring 53.5.

Five minutes, and when a link is the answer

At 1080p, our five-minute clip came back at 34,951,175 bytes whether we typed 13, 17 or 24. Each run took about 130 seconds and ended with the same note that the target could not be reached, and that file scored 42.4. At 720p, 24 gave 22,954,985 bytes in 29 seconds and scored 43.2, better than the heavier 1080p file. At 480p, 24 scored 44.1, while 17 gave 16,042,142 bytes and 13 gave 12,432,522, scoring 34.4 and 27.3. For our clip, five minutes under a 20 MB mail count meant 480p.

The page takes clips up to 200 MB and five minutes, and five minutes is exact. A version of our clip that ran 300.016 seconds, listed as 5:00, was turned away. If yours is longer, cut it with Trim Video first. If it has to stay long and sharp, send a link. Gmail makes one itself, and Mail Drop takes files up to 5 GB that expire after 30 days.

Compress Video runs in your browser with the browser's own encoder, and the video is not sent to our server. To continue in another tool, PulsarKit may store a local copy of your input or result in this browser. It can remain after you close the tab or restart the browser. Clear PulsarKit’s site data to delete it.