How to reduce a video’s file size without losing visible quality

Phone videos are big: a minute of 4K can take hundreds of megabytes, far too much to email, upload to a form or put on a website. The good news is that most of that size buys detail nobody sees on a phone or laptop. Here’s what actually makes a video large, and how to make it smaller without a visible drop in quality.

What makes a video file big

A video’s size is its bitrate (how much data each second gets) multiplied by its length:

size in MB ≈ bitrate in Mbps × seconds ÷ 8

So a 60-second clip at 8 Mbps is about 60 MB, and the same clip at 2 Mbps is about 15 MB. Every way of shrinking a video comes down to lowering the bitrate, the length, or both. Resolution matters because it decides how low the bitrate can go before the picture looks blocky: a 720p video looks clean at a bitrate where 4K would fall apart.

The quick way: compress to a target size

1. Open the video compressor and drop in the video. MP4, MOV, MKV, WebM and AVI all work.
2. Pick a target size, for example under 10 MB, or under 25 MB for an email. The tool works out the bitrate that fits.
3. Set the resolution to 1080p or 720p if the original is 4K.
4. Turn audio off if the video is meant to play muted, such as a website background.
5. Download the MP4.

The video is encoded on your own device with its hardware H.264 encoder, so it isn’t uploaded anywhere and there’s no length limit.

Five ways to reduce video size, biggest first

1. Lower the resolution. 4K has four times the pixels of 1080p and nine times those of 720p. On a phone or in an email preview, 1080p or 720p looks the same and needs a far lower bitrate.
2. Lower the bitrate. Phones record at a generous bitrate to be safe. Re-encoding at a sensible one is where most of the saving comes from, and a target size sets it for you.
3. Trim it. Size grows with length, so cutting a slow start or end is a free saving.
4. Remove the audio when nobody will hear it. Audio is a small part of most files, but on a short, heavily compressed clip it can be a large share.
5. Use an efficient codec. HEVC (H.265) and AV1 reach the same quality as H.264 at a lower bitrate, but not every device, browser and app plays them. H.264 MP4 is the format that plays everywhere, which is why our compressor outputs it.

How small can a video get?

Using the formula above, this is the total bitrate available for a target size:

As a rough guide, H.264 at 720p looks good from about 2–3 Mbps, and 1080p from about 4–5 Mbps. Below 1 Mbps, drop to 720p or 480p, or trim the video, rather than squeezing a high resolution into too little data.

Record smaller videos on your phone

Your camera’s video settings decide how big every new video is. On iPhone, Settings → Camera → Record Video lets you choose 1080p instead of 4K, and Settings → Camera → Formats → High Efficiency records HEVC, which takes less space. Android phones have similar options in the camera app’s settings. Recording at 1080p and 30 fps is plenty for most videos you’ll share.

Size limits where you’re sending it

• Email: Gmail and Yahoo allow 25 MB of attachments, Outlook.com about 20 MB. See how to send a large video by email.
• Discord: 20 MB on a free account. See Discord’s file size limit.
• Websites: a background or hero video should be a few megabytes at most; our web performance checklist covers why.

Frequently asked questions