video tool

Video file size calculator

A video's file size is its total bitrate times its length: megabits per second times seconds, divided by 8, gives megabytes. Enter the length and bitrate to get the size, or enter a size limit to get the bitrate that fits it, with presets from YouTube's recommended upload rates.

Loading the tool…

How it works

  1. 1

    Choose what you want

    The file size from a bitrate, or the bitrate that fits a size limit.

  2. 2

    Enter the length

    Minutes and seconds such as 1:30, or 90s, or 4m30s.

  3. 3

    Set the bitrates

    Pick a preset or type the video bitrate, and set the audio bitrate; 128 kbps is a common default.

  4. 4

    Read the result

    The size appears in MB and GB, or the bitrate to export at, with a few percent of headroom.

The formula

Bitrate is how much data a second of video uses, usually in megabits per second. Multiply by the number of seconds to get megabits, then divide by 8 because there are 8 bits in a byte. A one minute video at 8 Mbps with 128 kbps audio is 8.128 times 60 divided by 8, or about 61 MB. The same minute at 35 Mbps, a common 4K rate, is about 263 MB before audio. To go the other way, multiply the size limit in megabytes by 8, divide by the seconds, and subtract the audio bitrate.

Recommended bitrates

YouTube publishes recommended upload bitrates. For standard dynamic range video at 24, 25 or 30 frames a second it suggests 8 Mbps for 1080p and 35 to 45 Mbps for 4K; at 48 to 60 frames a second, 12 Mbps for 1080p and 53 to 68 Mbps for 4K. Those are upload recommendations, deliberately generous, because the platform re-encodes everything for viewing. Exporting much higher than recommended mostly makes the upload slower without making the result look better after processing.

Upload caps by platform

Upload limits vary a lot. LinkedIn's help pages list a maximum video file size of 5 GB, a 15 minute maximum length and bitrates from 192 kbps to 30 Mbps. The video builder's own uploads take video clips up to 200 MB, audio up to 25 MB and images up to 15 MB. Knowing the cap, enter it as the size limit and the length of your clip, and the calculator returns the highest bitrate that fits; export a few percent below it to leave room.

A table for quick estimates

The table under the result gives sizes for 30 seconds, one minute and five minutes at three rates: 1080p at 8 Mbps, 1080p at 60 frames a second at 12 Mbps, and 4K at 35 Mbps, each with 128 kbps audio. A one minute 1080p clip is around 60 MB, and five minutes of 4K is around 1.3 GB. Those figures help decide whether a clip can be emailed, which most mail services cap at around 20 to 25 MB, or needs a share link instead.

Why the exported file is not exactly this size

Most encoders use variable bitrate: simple scenes use less data and busy scenes more, aiming for an average. The finished file lands near the target, often within a few percent, but rarely exactly on it. Containers such as MP4 also add a little overhead for their indexes. When a hard limit matters, such as a 200 MB upload cap, aim about 5% under the calculated bitrate, which the tool suggests in its result.

Videos made in the video builder

The video builder renders its templates at 30 frames a second and exports landscape and vertical videos. Clips you upload into a scene must be 200 MB or less, so a long phone recording sometimes needs trimming or re-encoding first. The calculator tells you the bitrate that brings a clip of a given length under that limit.

Limits

  • A variable bitrate encode lands near its target, not exactly on it.
  • Container overhead, usually a percent or two, is not included.
  • Sizes use megabytes of 1,000,000 bytes, as upload limits usually do; a computer may show a slightly smaller number in mebibytes.
  • Bitrate is not quality on its own: codec, frame rate and content all change how good a given bitrate looks.

What it does not do

  • It does not encode or compress video.
  • It does not read a video file; the video metadata viewer does.
  • It does not store anything.

Questions people ask

How do I calculate video file size from bitrate?

Multiply the total bitrate in megabits per second by the length in seconds and divide by 8 to get megabytes. Two minutes at 10 Mbps video plus 0.128 Mbps audio is 10.128 times 120 divided by 8, about 152 MB. Add a percent or two for the container.

What bitrate does 1080p need?

YouTube recommends 8 Mbps for 1080p at 24 to 30 frames a second and 12 Mbps at 48 to 60, for standard dynamic range uploads. Efficient codecs such as H.265 can look good at lower rates. For a screen recording with little movement, much lower bitrates often look fine.

How big is a one minute 4K video?

At YouTube's recommended 35 to 45 Mbps for 4K at standard frame rates, one minute is roughly 260 to 340 MB plus audio. A phone recording at a lower 4K bitrate, often around 20 Mbps, is closer to 150 MB a minute. The exact size depends on the codec and settings used.

Does a higher bitrate always mean better quality?

Only up to a point. Beyond what the content needs, extra bitrate adds size without visible improvement, and platforms re-encode uploads to their own bitrates anyway. Codec, resolution and how much movement is in the shot matter as much. Fast action needs more bitrate than a talking head.

Why is my file smaller than the calculator says?

The encoder probably used variable bitrate and found simple scenes, such as static shots or a screen recording, that needed less data than the target. Constant bitrate encodes land closer to the figure. A file much larger than calculated usually means the bitrate setting was higher than you thought.

Make the video it is for

Take what you made here into videos.

Create a video with OneCraft

More tools like this

Background reading: the question page on this.

Sources

Written and checked by the OneCraft team. Last checked .