How to Compress a Video
Video files are big because they store a lot of pictures every second. This guide shows you how to make them smaller, what each setting really does, and how to keep your video looking good.
Why video files are so large
A video is a sequence of still pictures, usually 30 or 60 every second, plus sound. A single uncompressed frame of 1080p video holds about 6 MB of data, so one second would be 180 MB. Every video you have is therefore already compressed, often by a factor of 100 or more.
How big a compressed video ends up depends mostly on its bitrate: the amount of data stored for each second. Phones and cameras record at high bitrates, typically 15–50 megabits per second, so they capture as much detail as possible. That's useful for editing, but far more than you need to watch or share the video.
The size of a video file is simply:
file size ≈ bitrate × duration
A one-minute video at 20 Mbps is about 150 MB. The same minute at 2 Mbps is about 15 MB. That's why lowering the bitrate is the heart of video compression.
The four ways to make a video smaller
1. Lower the bitrate
Re-encoding a video at a lower bitrate is the most direct way to reduce its size. A modern encoder spends the available data on what your eyes notice, such as faces, edges and text, and saves it in flat or blurry areas. Lowering the bitrate by half often makes no visible difference on a phone screen.
2. Lower the resolution
Resolution is the number of pixels in each frame. Going from 1080p (1920 × 1080) to 720p (1280 × 720) cuts the number of pixels by more than half, so the same bitrate can describe each pixel in more detail, or you can lower the bitrate further. For videos watched on phones and laptops, 720p usually looks sharp.
3. Lower the frame rate
Gameplay and screen recordings are often captured at 60 frames per second. Most other videos look perfectly smooth at 30. Halving the frame rate frees up data for the frames you keep. Never raise the frame rate, though: it adds size without adding smoothness.
4. Trim what you don't need
Every second you remove is data you don't have to store. Cutting the slow start and the ending of a recording is often the easiest win of all, especially when you need to fit a strict limit such as 20 MB.
How to compress a video in your browser
The quickest way, on any device, is a browser-based compressor that doesn't upload your file:
- Open the Video Compressor.
- Tap Choose videos or drag your file onto the page. MP4, MOV, WebM, MKV, AVI and other formats work.
- Choose how to compress:
- Recommended for a big saving with little visible change.
- Target file size to aim for an exact number of megabytes.
- Presets for Discord, email, WhatsApp and Telegram.
- Optionally open Advanced settings to choose a resolution, frame rate or audio quality.
- Tap Compress video, wait for it to finish, and download the MP4.
The work happens on your own device, using its hardware video encoder when it has one, so private videos never leave it.
Compressing to an exact size
When a website or app has a hard limit, use Target file size. The compressor works out the bitrate for you:
bitrate (kbps) = size in MB × 8,192 ÷ duration in seconds − audio bitrate
For example, 20 MB for a 60-second video gives about 2,700 kbps in total. That's enough for sharp 720p. The same 20 MB for a 5-minute video gives only about 500 kbps, so the compressor automatically lowers the resolution to keep the picture clean.
Ready-made targets: 8 MB, 10 MB, 15 MB, Discord and email.
How small can a video get?
| Video length | Size for sharp 1080p | Size for sharp 720p | Size for 480p |
|---|---|---|---|
| 30 seconds | about 12 MB | about 6 MB | about 3 MB |
| 1 minute | about 24 MB | about 12 MB | about 6 MB |
| 5 minutes | about 120 MB | about 60 MB | about 30 MB |
These are typical values for everyday footage at 30 fps. Fast action, grain or noise needs more data; talking heads and screen recordings need less.
Compressing on your phone or computer
Every major platform has its own tools as well, and our device guides walk you through them step by step:
- Compress a video on iPhone
- Compress a video on Android
- Compress a video on Windows
- Compress a video on Mac
Common mistakes to avoid
- Zipping a video. Putting a video in a ZIP file barely changes its size, because the video is already compressed.
- Compressing a compressed copy. Each round of compression loses a little detail. Always start from the original.
- Keeping 4K for small screens. 4K is wasted on a phone or a chat window. Choose 1080p or 720p.
- Over-squeezing long videos. A ten-minute video in 10 MB will look poor whatever you do. Trim it, split it, or share a link.
Quick checklist
- Trim the start and end.
- Choose a resolution that suits the screen it will be watched on.
- Use 30 fps unless the video has fast action.
- Pick Recommended mode, or a target size if you have a limit.
- Watch the result before you send it.