Modern phones record beautiful video. They also record huge files. A few minutes of 4K at 60 frames per second can easily pass a gigabyte, and the person you're sending it to is probably going to watch it on a laptop screen or a phone.

Most of the time you can make the file five to ten times smaller and nobody will notice.

Why phone videos are so big

Video size comes down to one number: bitrate, measured in megabits per second (Mbps). It's how much data the file uses for each second of footage.

Phones use high bitrates because they're recording live and can't spend time on efficient compression. Rough ballpark figures:

4K at 60fps: around 50-60 Mbps, or about 400MB per minute
4K at 30fps: around 35-45 Mbps
1080p at 30fps: around 10-17 Mbps

Exact numbers depend on the phone and whether it's saving as H.264 or HEVC (H.265), but the point stands. A video encoded on a computer, where the encoder can take its time, can look nearly the same at a fraction of the bitrate.

The math that tells you the final size

File size in megabytes is roughly:

bitrate (Mbps) × length (seconds) ÷ 8

So a 5-minute video (300 seconds) at 8 Mbps comes out to about 300MB. At 4 Mbps, about 150MB. Audio adds a little on top, usually 1-2MB per minute.

That's handy when you have a target. If you need a 10-minute clip under 500MB, you need an average bitrate under about 6.5 Mbps.

Using HandBrake (free, Windows/Mac/Linux)

HandBrake is the standard free tool for this. It looks intimidating, but you only need a handful of settings.

Open HandBrake and drag your video in.
Under Preset, pick General → Fast 1080p30. This is a sensible starting point for almost everything.
On the Video tab, look at the Constant Quality slider (labeled RF). Lower numbers mean better quality and bigger files.
Choose where to save it, then click Start Encode.

For the RF value, these are reasonable starting points for 1080p with the H.264 encoder:

RF 20: very close to the original, still much smaller
RF 22-23: good default for sharing
RF 26+: noticeably softer, fine for a quick preview

If you switch the encoder to H.265 (HEVC), you can get the same quality at an even smaller size, but older computers and some web players handle it less smoothly. H.264 is the safe choice when you don't know what the recipient has.

Do you actually need 4K?

Probably not. Unless the recipient is going to edit the footage or show it on a big 4K display, 1080p is enough. Dropping from 4K to 1080p alone cuts the pixel count by four.

Frame rate matters too. 60fps is great for fast motion like sports, but for someone talking to the camera, a walkthrough or a screen recording, 30fps looks the same and needs less data.

Screen recordings are a special case

Screen recordings are often mostly static: a slide, a spreadsheet, a cursor moving around. They compress extremely well. A 20-minute screen recording at 1080p can often fit in 100-200MB without any visible loss, because most frames barely change.

If your screen recording is still huge, check the frame rate. Some recorders default to 60fps, which is pointless for a slideshow.

Quick alternatives

On a Mac: open the video in QuickTime Player, go to File → Export As, and pick 1080p. Fast and decent, though you get less control.
On an iPhone: under Settings → Camera → Record Video, you can switch future recordings to 1080p if you know you'll be sending them.
On Windows: the built-in Clipchamp editor can export at 480p, 720p or 1080p.

When not to compress

If the recipient is a video editor, a client who paid for raw footage, or anyone who'll process the video further, send the original. Every re-encode loses a bit of quality, and they'll want to make their own compression decisions.

In that case, the file is going to be big no matter what. Use a transfer link rather than trying to squeeze it into an email or chat app, and tell them roughly how large it is so they know the download will take a while.

The short version

Drop to 1080p unless 4K is truly needed.
Use 30fps unless there's fast motion.
HandBrake, Fast 1080p30 preset, RF around 22.
Check the result on a real screen before sending.

Ten minutes of setup the first time, and after that it's drag, click, done.

How to Shrink a Video Before Sending It (Without Making It Look Bad)