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How Much Storage Does 4K Video Use?

Storage for 4K video is set by bitrate and duration, not by the word "4K". This guide shows the arithmetic, works through a ten-minute clip at published upload bitrates, and points you at the calculator for your own figures.

Published 2026-08-11 · Updated date pending

The short answer

Resolution alone does not determine file size. Bitrate and duration do. A 4K file recorded at 100 Mbps is roughly three times the size of a 4K file delivered at 35 Mbps, even though both are 3840x2160. To get a number, multiply the bitrate by the duration and divide by eight.

Ten minutes of 4K at 35 Mbps video plus 384 Kbps audio comes to 2.65 GB. The same ten minutes at a camera’s 100 Mbps recording mode is far larger. Put your own bitrate and duration into the Video File Size Calculator and it will do the conversion for you.

The one formula everything else rests on

A bitrate is a count of bits per second. A file size is a count of bytes. One byte is eight bits, a relation NIST states directly in its note on SI and binary prefixes. So the whole calculation is a multiplication and a division:

totalBitrate = videoBitrate + audioBitrate
payloadBits  = totalBitrate x durationSeconds
fileSizeBytes = payloadBits / 8

Two conventions matter here and both come from the same NIST note. In SI, kilo means 10^3, mega means 10^6, and giga means 10^9. This site uses those decimal meanings throughout: 1 GB is 1,000,000,000 bytes. The binary quantities, where a gibibyte is 2^30 bytes, have their own names and symbols, GiB among them. Mixing the two is the single most common reason a hand calculation disagrees with what an operating system reports.

Bitrates have no binary variant at all. A megabit per second is 1,000,000 bits per second, never 1,048,576.

YouTube publishes a table of recommended upload bitrates. For 2160p standard dynamic range at 24, 25 or 30 frames per second it recommends 35 to 45 Mbps, and it recommends 384 kbps for stereo audio. Take the bottom of that range and a ten-minute clip:

videoBitrate  = 35 Mbps        = 35 000 000 bps
audioBitrate  = 384 Kbps       =    384 000 bps
totalBitrate  = 35 384 000 bps
duration      = 10 min         =        600 s
payloadBits   = 35 384 000 x 600   = 21 230 400 000 bits
fileSizeBytes = 21 230 400 000 / 8 =  2 653 800 000 bytes
              = 2.65 GB

Per minute that is 265.38 MB. A full hour at the same settings is 15.92 GB. Take the top of YouTube’s range instead, 45 Mbps, and the ten minutes becomes 3.40 GB. The resolution never entered the arithmetic. Only the bitrate did.

You can reproduce every line of that in the Video File Size Calculator by entering 10 minutes, 35 Mbps, and 384 Kbps of audio.

Recording bitrates are much higher than delivery bitrates

The numbers above are delivery bitrates: what a platform asks you to upload. Camera recording bitrates are a different and usually larger set of numbers, because a recording format is trying to survive an edit rather than reach a viewer once.

Sony’s help guide for the FDR-AX30 series documents its XAVC S 4K modes at approximately 100 Mbps and approximately 60 Mbps, both at 3,840 x 2,160 pixels, alongside an XAVC S HD mode at approximately 50 Mbps at 1,920 x 1,080. That is one manufacturer and one product family, and it is quoted here only to show the scale of the gap: a documented 4K recording mode can be roughly three times a documented 4K delivery bitrate.

Your camera’s own manual is the authority for your camera. This site does not publish a table of recording bitrates by model, because such a table would be wrong somewhere the day it was written and would go on being wrong silently. Read your bitrate off your camera’s specification, then put it into the calculator.

Why “4K” is not a file size

4K describes a frame size. YouTube’s resolution table lists 2160p as 3840x2160 pixels. That tells you how many pixels each frame contains, and nothing about how many bits the encoder spends describing them.

The encoder decides that, guided by whatever bitrate or quality target you gave it. The same 3840x2160 frame can be encoded at 8 Mbps or 200 Mbps. Both are 4K. Their file sizes differ by a factor of twenty-five. This is why every honest storage estimate starts with a bitrate, and why a tool that asks only for a resolution is guessing on your behalf.

Frame rate reaches file size the same indirect way. YouTube’s table recommends 53–68 Mbps for 2160p at 48, 50 or 60 fps against 35–45 Mbps at the standard rates, so the higher frame rate arrives as a higher recommended bitrate, and the bitrate is what the arithmetic consumes.

What this does not tell you

  • The estimate assumes the stated bitrate is the achieved average. A variable-bitrate encode aims at an average and varies around it. If the encoder lands under its target on simple footage, the real file is smaller than the estimate. Why your actual file size differs covers the reasons in detail.
  • Container overhead is not included by default. The calculator’s overhead field defaults to zero, which gives you the raw payload. The real figure depends on your container and muxer, and this site does not publish a number it has not measured.
  • A card’s usable capacity is smaller than its printed capacity. Formatting and any existing content take space that the arithmetic above does not know about.
  • No codec efficiency is assumed anywhere. The formula does not know or care which codec produced the bitrate you typed.

Frequently asked questions

How much storage does one hour of 4K video use?

At 35 Mbps video plus 384 Kbps audio, one hour is 15.92 GB. At 45 Mbps it is 20.42 GB. There is no single answer, because the answer is set by the bitrate you record or export at. Enter your own bitrate in the Video File Size Calculator.

Does 4K always use four times the storage of 1080p?

No. It uses whatever its bitrate implies. Comparing YouTube’s own recommended SDR figures, 2160p at 35 Mbps against 1080p at 8 Mbps, a ten-minute clip goes from 628.80 MB to 2,653.80 MB, a ratio of 4.22 rather than exactly 4. Change either bitrate and the ratio changes with it.

Why does my computer report a smaller size than this calculation?

Almost always because it is reporting binary units. NIST’s note sets out the two systems: 1 GB is 10^9 bytes, while 1 GiB is 2^30 bytes, which is 1,073,741,824 bytes. A file of 2,653,800,000 bytes is 2.65 GB or 2.47 GiB. The file did not change; the unit did.

Should I use the recording bitrate or the export bitrate?

Use whichever file you are trying to size. For card planning, use the recording bitrate from your camera’s specification and the recording time calculator. For an upload or a delivery file, use the export bitrate.

Does turning audio off change the answer much?

Rarely at 4K. At 35 Mbps video, a 384 Kbps audio track is about 1.1% of the total bitrate. At low video bitrates the audio share becomes significant, which is why the calculator lets you switch it off and set its bitrate.

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