How do I compress a video to send by email?

Open the video, check the number in Target and press Compress. Keep MP4, which carries H.264 video and AAC sound, so the person you send it to can play it on nearly any device. Compare the original and the result side by side, press Download, then attach the downloaded file to the email.

What if my mail service has a different limit?

Type about three quarters of the limit into Target, or less: three quarters of 20 MB is 15 MB, and three quarters of 25 MB is 18.75 MB. Other attachments and the message itself share the same allowance, so leave more room when one email carries several files.

My video is too long to fit. What can I change?

A three-minute 1920 x 1080 clip at 30 fps gets 512 kbps for the picture at a 15 MB target, after 128 kbps of sound, which is under the page's 0.01 bits per pixel per frame floor, so the page refuses and names width 1280 or smaller, 24 fps or lower, No audio, or a larger target. At width 1280 the same bitrate is about 0.019 bits per pixel per frame, above the 0.01 floor. For a clip that will not fit at any sensible size, sharing a link from a cloud drive is usually better than an attachment.

Does it work for an iPhone or Android video?

Yes, in a current browser on the phone itself or on a computer, with nothing to install: tap Open video and pick the clip from your photo library or files. The page checks that your browser can decode the clip and write the format before it starts, and names what is missing if it cannot. If the video is already smaller than 15 MB, that target is refused because it would not compress anything, and the file may already be small enough to attach.

Compress a Video for Email

Open a clip and this page already has 15 MB in Target. Mail sends an attachment as text, which adds roughly a third to its size, so a 15 MB file takes about 20 MB of a message limit before the rest of the email is counted. The plan shows the bitrate the picture gets before encoding, and the finished size is measured on the real file. The video is compressed in this browser tab and never uploaded here.

Open a video to compress

· or drop one anywhere on the stage

Never uploadedNo accountUp to 250 MBUp to 10 minutes

Target: MB

Width

Frame rate

Audio

Format

Download

Ready. Choose a video, or drop one on the stage.

1920 x 1080 to width 960aspect ratio kept, both sides even
960 x 540
Ten-second source at 30 fpsthe finished file is read back
kept within one frame (33.3 ms), or the result says by how much it missed
40 s clip into 50,000 Ba 10 kbps target, under the 128 kbps audio
refused before encoding, the audio alone needs 640,000 B

The target is split before anything is encoded: 96 per cent of it, in bits, divided by the length, less the audio, is the bitrate the picture gets, so the file aims 4 per cent under the target to leave room for the container. Width sets the output width, and the height follows the original shape, rounded to an even number because the encoders need one. A frame rate cap only ever lowers the rate. Keep copies the original sound without re-encoding it where the format can hold it (AAC or MP3 in an MP4, Opus or Vorbis in a WebM) and it starts at the zero point of the file; otherwise the message says why and asks for a bitrate. When the work ends, the file is read back: its container, codecs and picture size must match the plan or it is not offered, and its size and length are measured, not predicted.

Accuracy. Which codecs can be read and written depends on your browser, and an unsupported file or encoder is refused before any encoding starts, never written under the wrong label. The target sets the bitrate, so the file lands near it rather than on it, and the finished size and duration are measured on the real file. Videos up to 250 MB and 10 minutes are compressed on your device and never uploaded.

The encoding is done by your browser, and the file handling by one open source library served from this site. Containers are read and written by Mediabunny 1.55.7 under the MPL-2.0 (licence text, the exact package, source), bundled unmodified. Compressed video and sound are decoded and encoded by the WebCodecs codecs built into your browser, which is why the formats on offer depend on it.

Common questions

How do I compress a video to send by email?: Open the video, check the number in Target and press Compress. Keep MP4, which carries H.264 video and AAC sound, so the person you send it to can play it on nearly any device. Compare the original and the result side by side, press Download, then attach the downloaded file to the email.
What if my mail service has a different limit?: Type about three quarters of the limit into Target, or less: three quarters of 20 MB is 15 MB, and three quarters of 25 MB is 18.75 MB. Other attachments and the message itself share the same allowance, so leave more room when one email carries several files.
My video is too long to fit. What can I change?: A three-minute 1920 x 1080 clip at 30 fps gets 512 kbps for the picture at a 15 MB target, after 128 kbps of sound, which is under the page's 0.01 bits per pixel per frame floor, so the page refuses and names width 1280 or smaller, 24 fps or lower, No audio, or a larger target. At width 1280 the same bitrate is about 0.019 bits per pixel per frame, above the 0.01 floor. For a clip that will not fit at any sensible size, sharing a link from a cloud drive is usually better than an attachment.
Does it work for an iPhone or Android video?: Yes, in a current browser on the phone itself or on a computer, with nothing to install: tap Open video and pick the clip from your photo library or files. The page checks that your browser can decode the clip and write the format before it starts, and names what is missing if it cannot. If the video is already smaller than 15 MB, that target is refused because it would not compress anything, and the file may already be small enough to attach.

Which codecs can be read and written depends on your browser, and an unsupported file or encoder is refused before any encoding starts, never written under the wrong label. The target sets the bitrate, so the file lands near it rather than on it, and the finished size and duration are measured on the real file. Videos up to 250 MB and 10 minutes are compressed on your device and never uploaded.