How Big Is a Video File? Size per Minute by Resolution

The formula

Video file size

megabytes = bitrate in Mbps × seconds ÷ 8

Bitrate is the number of bits the file uses for each second of video, usually given in megabits per second (Mbps). There are 8 bits in a byte, so the division by 8 turns megabits into megabytes. Audio has its own bitrate, which you add to the video bitrate before multiplying.

This page counts in decimal units: 1 MB is 1,000,000 bytes and 1 GB is 1,000,000,000 bytes, the same way bitrates are counted. If a file manager shows sizes in binary units (1 GiB = 1,073,741,824 bytes), the same file shows a number about 7 percent smaller. The data storage converter switches between the two.

Size per minute and per hour by resolution

YouTube publishes recommended bitrates for uploads, split into standard frame rates (24, 25 and 30 frames per second) and high frame rates (48, 50 and 60). They are a useful reference because they describe ordinary H.264 video in an MP4 file, the most common format around. Video only, without audio:

Resolution	Frame rate	Bitrate	MB per minute	GB per hour
2160p (4K)	24 to 30	35–45 Mbps	263–338	15.8–20.3
2160p (4K)	48 to 60	53–68 Mbps	398–510	23.9–30.6
1440p	24 to 30	16 Mbps	120	7.2
1440p	48 to 60	24 Mbps	180	10.8
1080p	24 to 30	8 Mbps	60	3.6
1080p	48 to 60	12 Mbps	90	5.4
720p	24 to 30	5 Mbps	38	2.3
720p	48 to 60	7.5 Mbps	56	3.4
480p	24 to 30	2.5 Mbps	19	1.1
480p	48 to 60	4 Mbps	30	1.8
360p	24 to 30	1 Mbps	8	0.5
360p	48 to 60	1.5 Mbps	11	0.7

Stereo audio at the recommended 384 kbps adds 2.88 MB per minute, or 0.17 GB per hour. For 1080p at 30 frames per second that brings the total to about 63 MB a minute. Two quick rules fall out of the arithmetic: MB per minute is the bitrate in Mbps times 7.5, and GB per hour is the bitrate times 0.45.

Treat these as a reference, not a promise. A phone, a camera or a screen recorder picks its own bitrate, and the file details (or the properties panel of a video player) show what it actually used.

A 1080p recording at different lengths

At 8 Mbps video plus 384 kbps audio, 8.384 Mbps in total:

Length	Size
1 min	63 MB
5 min	314 MB
10 min	629 MB
30 min	1.89 GB
60 min	3.77 GB
120 min	7.55 GB

Keep bits and bytes apart when you compare a file with a connection. Internet speeds are quoted in megabits per second, file sizes in megabytes, so a 100 Mbps line moves at most 12.5 MB per second. An hour of it is 3.77 GB. Sending that over a 100 Mbps connection takes about 5.0 minutes at full speed; the download time calculator does the same sum for your own file and connection.

How much video fits under a size limit

Turn the formula around to see how long a clip can be: seconds = megabytes × 8 ÷ total bitrate. With stereo audio at 384 kbps included:

Size limit	1080p, 8 Mbps	720p, 5 Mbps	480p, 2.5 Mbps
25 MB	0:23	0:37	1:09
100 MB	1:35	2:28	4:37
500 MB	7:57	12:22	23:06
1 GB	15:54	24:45	46:13
4 GB	1.1 h	1.7 h	3.1 h

A 25 MB email attachment holds less than half a minute of 1080p video at these rates. The email attachment limits guide lists what each provider accepts. To fit a fixed length into a fixed size, divide instead: a 2-minute clip under 25 MB needs a total bitrate of at most 25 × 8 ÷ 120 = 1.67 Mbps.

Why two files of the same length differ

Bitrate setting. It sets the size directly. MDN puts it plainly: higher bit rates lead to larger output files.
Resolution and frame rate. More pixels and more frames per second need more bits. In YouTube's table, going from 30 to 60 frames per second at 1080p raises the bitrate by half, from 8 to 12 Mbps.
Motion and noise. Codecs save space by storing what changes between frames. MDN notes that the more motion there is, the larger the output file will typically be, and grainy low-light footage compresses worse for the same reason. A talking head against a wall is cheap; a handheld walk through a crowd is not.
Codec. Newer codecs do more with each bit. Apple says HEVC offers better compression than H.264 while preserving the same visual quality, which is why iPhones record HEVC under the High Efficiency camera setting and H.264 under Most Compatible.
Editing formats. Formats made for editing keep far more data per frame. Apple states that ProRes files are up to 30 times larger than HEVC files, so a minute that is 100 MB in HEVC can be as much as 3 GB in ProRes.

How to make a video file smaller

Every fix works on one side of the formula: fewer seconds or fewer bits per second.

Cut what you do not need. Trim the video first. Removing 20 seconds from a 60-second clip removes about a third of the file without touching quality.
Lower the resolution to the size it is watched at. A clip shown in a chat window or an email does not need 4K. Dropping from 1080p to 720p at YouTube's rates takes the bitrate from 8 to 5 Mbps, a cut of 37.5 percent.
Lower the bitrate. The video compressor re-encodes the file at a lower resolution and bitrate in your browser. Halving the bitrate halves the file.
Pick an efficient codec and container. The MP4 vs WebM vs MOV guide explains which combinations play where.

The cheapest saving happens before you record. On an iPhone, Apple's camera setting under Settings, Camera, Formats decides the codec: High Efficiency records HEVC, Most Compatible records H.264, and Apple says HEVC gives better compression at the same visual quality. The same Camera settings choose the resolution and frame rate, so a clip meant for a chat or a quick email can be recorded at 1080p and 30 frames per second instead of 4K and 60. In YouTube's table that is the difference between 53–68 Mbps and 8 Mbps.

Each re-encode with a lossy codec drops a little more detail, so compress from the original and do it once. The lossy vs lossless guide explains why a second pass never brings the lost detail back.

A worked example: a 10-minute 1080p screen recording at 8 Mbps plus audio is about 629 MB. Trimmed to 7 minutes and re-encoded at 720p and 5 Mbps, it becomes 283 MB, 55 percent smaller.

Frequently asked questions

How many MB is one minute of 1080p video?

At the 8 Mbps that YouTube recommends for a 1080p upload at 24 to 30 frames per second, one minute is 60 MB of video, plus about 3 MB for stereo audio at 384 kbps. At 60 frames per second the recommendation is 12 Mbps, or 90 MB a minute. A phone or a screen recorder may use a different bitrate, so check the file itself.

How big is an hour of 4K video?

At YouTube's recommended 35 to 45 Mbps for 4K at standard frame rates, an hour is 15.8 to 20.3 GB. At 60 frames per second (53 to 68 Mbps) it is 23.9 to 30.6 GB. A professional recording format at a far higher bitrate can be many times that.

Why is my 10-second video bigger than a 1-minute video?

Because the size depends on the bitrate, not only the length. A clip recorded at 4K and 60 frames per second can carry more than ten times the bits per second of a 720p clip, and MDN notes that more motion and more noise also make the compressed file larger. Look at the bitrate in the file details, not the duration.

How do I calculate the size of a video?

Multiply the total bitrate in megabits per second by the length in seconds and divide by 8 to get megabytes. 8 Mbps for 90 seconds is 8 × 90 ÷ 8 = 90 MB. Add the audio bitrate to the video bitrate first if you want the full file.

Does a video lose quality when I make it smaller?

Almost always, because the common video codecs are lossy and a smaller file means fewer bits for each second. MDN describes it as a tradeoff of size versus quality. Lowering the resolution to the size the video is actually shown at usually costs less visible quality than squeezing the bitrate at full resolution.

Sources

Written by Tobias. Updated October 26, 2026.