How many MB is a minute of video?

A minute of video has no fixed size. The same minute of 1080p can be 15MB from a streaming service and 200MB from a phone, and both are correct for what they were made for.

What decides it is one number: the bitrate, which is how many bits the encoder was allowed to spend per second. Resolution, frame rate and codec all matter only through their effect on it.

The arithmetic

size in MB = bitrate in Mbps x seconds / 8

So a 10 Mbps file is 1.25MB per second, 75MB per minute, 750MB for ten minutes. Everything in the tables below is that formula, with typical bitrates filled in.

(The division by 8 is bits to bytes. The other place people lose a factor is MB versus MiB: a 75MB file shows as 71.5MB on Windows, and both are right.)

Size per minute, by resolution

Three columns, because "a 1080p video" means three different things depending on where it came from.

Resolution	Streaming quality	Phone recording	Screen recording
480p	1.5 Mbps, 11MB/min	—	1 Mbps, 7.5MB/min
720p	3 Mbps, 22MB/min	5 Mbps, 38MB/min	2 Mbps, 15MB/min
1080p	5 Mbps, 38MB/min	12–17 Mbps, 90–130MB/min	4 Mbps, 30MB/min
1440p	10 Mbps, 75MB/min	20 Mbps, 150MB/min	8 Mbps, 60MB/min
4K	20 Mbps, 150MB/min	45–100 Mbps, 340–750MB/min	15 Mbps, 110MB/min

Streaming quality is roughly what YouTube or Netflix deliver at that resolution, encoded carefully with a slow encoder. It is the smallest a minute can reasonably be without looking worse than its resolution.

Phone recording is what comes out of a camera app. Phones encode in real time with a hardware encoder that has no time to be clever, so they spend two to four times the bits for the same picture. A minute of iPhone 4K at 60 fps is around 400MB, and the phone's own settings screen says so.

Screen recording is cheaper than either because most of the frame does not change from one moment to the next. A recording of a slide deck with a cursor moving is nearly free; a recording of a game is a phone video.

Why phone video is so much bigger

Three reasons, in order of size.

Real-time encoding. The phone has 33 milliseconds per frame to encode, so it cannot search hard for the best way to describe each one. It compensates with bitrate. A re-encode on a laptop with time to spare routinely gets the same picture at a third of the bytes, which is the whole reason compressing a phone video works so well.

Frame rate. 60 fps is twice as many frames as 30 fps. Encoders do not quite double the size, because consecutive frames are more similar at 60 fps, but 50–70% larger is typical.

Resolution you did not ask for. Many phones default to 4K. Four times the pixels of 1080p, two and a half to four times the bytes, and shown on a screen that cannot display the difference.

Worked examples

A 3-minute 1080p phone video, 300MB. That is about 13 Mbps. Re-encoded at 5 Mbps it is 112MB and looks the same; at 2.5 Mbps it is 56MB and looks slightly softer in motion. A 100MB target gets 4.4 Mbps, which is comfortably above the point where 1080p starts to suffer.

A 20-second clip for Discord's 20MB limit. Twenty seconds into 20MB is 8 Mbps, which is more than a streaming service uses for 1080p. The clip will come out fine at full resolution.

A 45-minute lecture recording into 100MB. That is 300 kbps, which is below what 480p needs to stay watchable. This is the honest case where the limit cannot be met at a quality anyone would accept, and a tool that produces a file anyway has produced mud. The answer is to split it, or send a link.

The threshold between those last two is the thing to know: below roughly 1.5 Mbps at 1080p and 0.8 Mbps at 720p, the picture falls apart in motion. Where the line sits for each resolution decides whether a size target is achievable or not.

The quick reference the other way round

The question people actually have is usually "how long a video fits in this limit". Dividing the limit by a watchable bitrate:

Limit	At 1080p (4 Mbps)	At 720p (2 Mbps)	At 480p (1 Mbps)
8MB	16 s	32 s	64 s
16MB (WhatsApp)	32 s	64 s	2 min
20MB (Discord)	40 s	80 s	2.7 min
25MB (Gmail, nominal)	50 s	100 s	3.3 min
50MB	100 s	3.3 min	6.7 min
100MB (Teams chat)	3.3 min	6.7 min	13 min

Each column is the length at which the video still looks like its resolution. Longer than that, and dropping a rung is better than squeezing the one you have: 720p at 2 Mbps looks better than 1080p at 2 Mbps, every time.

Why the table cannot be exact

Two videos at the same bitrate are the same size. Two videos at the same quality are not: a talking head against a plain wall compresses to a fraction of what a football match needs, because the encoder only spends bits on what changes.

That is also why an encoder told to hit a bitrate does not quite hit it. Constant-bitrate mode undershoots on still content and overshoots on motion, and the overshoot is what turns a 19.6MB target into a 20.4MB file that fails to upload.

Compress a video to 20MB, to 50MB or to 100MB works from the formula above, picks the highest resolution the budget supports, encodes on your own machine, weighs the actual output and re-encodes if it came in over. The file is never uploaded, so the second pass costs seconds rather than a second upload.

FAQ

How many MB is a 1 minute video?

Between 10MB and 400MB, depending on resolution and who encoded it. A minute of 1080p is about 38MB at streaming quality and 90–130MB straight from a phone. A minute of 4K is 150MB at streaming quality and 350MB or more from a phone at 60 fps. The formula is bitrate in megabits per second, times seconds, divided by eight.

How big is a 10 minute 1080p video?

Roughly 375MB at a streaming-service bitrate of 5 Mbps, and 900MB to 1.3GB straight from a phone, which records at 12–17 Mbps. Re-encoding the phone version at 5 Mbps gets it to around 375MB with no visible change, because the phone was spending extra bits to keep up in real time rather than to add detail.

How much space does 4K video take per minute?

About 150MB per minute at a careful 20 Mbps encode, and 340–750MB per minute straight from a phone, where 4K at 60 fps commonly records at 45–100 Mbps. It is the frame rate as much as the resolution: 4K at 30 fps is roughly 40% smaller than the same clip at 60 fps.

Does a longer video have to be lower quality to fit a size limit?

Yes, and linearly: the limit buys a fixed number of bits, and a video twice as long gets half as many per second. Twenty seconds into 20MB is 8 Mbps, which is excellent 1080p. Two minutes into the same 20MB is 1.3 Mbps, where 1080p falls apart and 720p is the better choice. Past about ten minutes into 20MB, no resolution looks acceptable and the answer is a link rather than a file.