How to make a video small enough to email or send in chat
The simple maths behind video file size, the two settings that change it, and why a GIF is usually the wrong choice.
Why phone videos are so big
A video's file size is its bitrate multiplied by its length. Bitrate is how much data the video uses each second, and phones record at high bitrates so the footage holds up if you edit it or watch it on a big screen. A phone recording 1080p video typically uses somewhere around 10 to 20 megabits per second, which works out at roughly 75 to 150 MB for every minute. 4K recordings are several times larger again.
Email cannot carry that. Gmail limits attachments to 25 MB and other email services set similar limits, and many chat apps and forums refuse or heavily recompress large videos. A one-minute clip has to shrink to a fraction of its size to get through.
Working out the size you need
Because size is bitrate times length, you can work backwards. To send one minute of video in a 25 MB email, the video can average about 3.3 megabits per second, sound included. A two-minute clip gets half of that. This table shows the budget for one minute at a few target sizes, and the resolution that bitrate comfortably supports:
| File size for one minute | Average bitrate | Comfortable resolution |
|---|---|---|
| 10 MB | about 1.3 Mbit/s | 854 px wide (480p) |
| 25 MB | about 3.3 Mbit/s | 1280 px wide (720p) |
| 50 MB | about 6.7 Mbit/s | 1920 px wide (1080p) |
The two settings that matter
Resolution is the bigger lever. A 1920-pixel-wide video has more than twice the pixels of a 1280-pixel one, and four times those of 960 pixels, so lowering the width cuts the bitrate a video needs to look good. On a phone screen, a 1280-pixel-wide video looks practically identical to the original, and 854 pixels is fine for most chat messages.
Quality is the second lever. Smushify's quality slider sets how hard the encoder compresses each frame: around 70 is the recommended balance, 50 to 60 gives noticeably smaller files that still look fine on a phone, and below about 40 you start to see blocky patches in fast motion. Unlike a fixed bitrate, a quality setting gives simple scenes fewer bits and busy ones more, which keeps the picture even.
Shrinking a video in your browser
Drop the video into the converter below. It starts with MP4 at 1280 pixels wide and quality 70, which plays on every phone, computer and browser and suits email and chat. Click Convert and the card shows the new size next to the original. If it is still too big, lower the width to 854 pixels or the quality to around 55 and click Re-convert; there is no target size for video, so this check takes one or two tries. Videos wider than 1920 pixels, including 4K, always come out at 1920 at most.
Smushify accepts MP4, MOV from iPhones, WebM, MKV and AVI, and converts several videos in a batch. Everything runs on your own device, so nothing is uploaded, and location and other metadata from the phone are removed. Encoding video is heavy work, though: a short clip takes seconds, but a long or high-resolution video can take several minutes, especially on a phone. Keep the tab open until it finishes.
MP4 or WebM?
For sending to people, choose MP4 (H.264 video with AAC audio). It plays everywhere, including iPhones, Windows and every chat app. WebM is an open format that suits videos embedded on a website; it plays in all current browsers but is less welcome as an attachment.
When a GIF is the wrong choice
It is tempting to turn a short clip into a GIF so it plays automatically, but GIF is a format from 1987. It has no sound, at most 256 colours per frame, and none of the motion compression that video formats use, so GIFs are almost always far larger than the video they came from. When we converted a 3-second iPhone clip of 3.7 MB, the GIF came out at 8.8 MB, more than twice the size, even at 480 pixels wide and 15 frames per second.
Use a GIF only where nothing else is accepted, and keep it short and small. Everywhere else, a muted MP4 does the same job in a fraction of the size, and most chat apps and websites play it automatically. If you already have a large GIF, converting it to MP4 usually makes it many times smaller.
When a link is better than an attachment
For long videos that need to keep their full quality, an attachment is the wrong tool. Gmail turns attachments over 25 MB into Google Drive links, and Mail on iPhone and Mac offers Mail Drop for large files. Shrink the video when the person just needs to watch it on a phone; share a link when they need the original.
Try it: Compress video
Open the Compress video converter. It runs in your browser, so nothing is uploaded.
Frequently asked questions
How long can a video be to fit in an email?
At about 3 Mbit/s, which looks good at 1280 pixels wide, roughly one minute fits in Gmail's 25 MB. At 854 pixels and a lower quality you can fit two to three minutes.
Does compressing a video lower its quality?
Some detail is lost, but at 1280 pixels wide and quality 60 to 70 the difference is hard to see on a phone. Keep the original if you may want to edit it later.
Can I compress a video on my iPhone?
Yes. Open Smushify in Safari, switch to the Videos tab and add the video from your library. It converts on the phone itself, which takes longer than on a computer for long clips.
Are my files uploaded anywhere?
No. Smushify converts everything inside your browser using WebAssembly. Your files are never sent to a server, so it is safe for private photos and documents.
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