Uncompressed Image & Video Size Calculator

Understanding the uncompressed image and video size calculator — concept and principle

This calculator estimates how much memory or storage a picture or a video takes before any compression. It is used to size frame buffers and GPU memory, plan capture-card and storage throughput, choose cables and interfaces, and understand why codecs such as JPEG, H.264 or HEVC are indispensable.

Pixels × 3 bytes gives one 4K frame; multiply by frames and seconds for raw video.

How it is calculated

Image size (MB) = width × height × bits per pixel ÷ 8 ÷ 1,000,000
Raw video size (GB) = width × height × bits per pixel ÷ 8 × fps × seconds ÷ 1,000,000,000
Raw video bitrate (Gbps) = width × height × bits per pixel × fps ÷ 1,000,000,000

Width and height are in pixels. Bits per pixel is the colour depth: 8 for greyscale, 24 for 8-bit RGB, 32 for RGBA, 30 or 36 for 10- or 12-bit RGB. Dividing by 8 turns bits into bytes. The results use decimal units (1 MB = 10^6 bytes, 1 GB = 10^9 bytes, 1 Gbps = 10^9 bits per second).

The principle

A raster image is a grid of pixels, and every pixel stores the same fixed number of bits, so the size is simply the pixel count times the bits per pixel. Video is a sequence of such frames: multiply one frame by the frame rate to get bits per second, and by the duration to get the total. Nothing here depends on the picture content; that is exactly what "uncompressed" means. Real video often uses 4:2:0 chroma subsampling (about 12 bits per pixel at 8-bit depth); enter that effective value to model it.

Worked example

Inputs: 3840 × 2160 pixels (4K UHD), 24 bits per pixel, 30 fps, 60 seconds.
Pixels per frame: 3840 × 2160 = 8,294,400.
Bits per frame: 8,294,400 × 24 = 199,065,600 bits = 24,883,200 bytes, so the image is 24.8832 MB.
Bitrate: 199,065,600 × 30 = 5,971,968,000 bit/s = 5.971968 Gbps.
One minute: 24,883,200 × 30 × 60 = 44,789,760,000 bytes = 44.78976 GB.

Each point is the calculator re-run with only “Width (px)” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Width (px)	Image (MB)
960	6.2208
1,920	12.4416
2,880	18.6624
3,840	24.8832
4,800	31.104
5,760	37.3248
7,680	49.7664

How to read the result

The image size tells you the RAM a single decoded frame occupies, regardless of whether it came from a 2 MB JPEG. The bitrate is the sustained throughput a raw capture or link must carry; compare it with the interface: 4K30 RGB at about 6 Gbps is why uncompressed 4K needs a high-bandwidth link, while a streamed 4K video at 15–25 Mbps is several hundred times smaller. The GB figure shows how quickly raw recording fills a drive.

Common mistakes

Forgetting to divide by 8 and reporting bits as bytes.
Mixing decimal MB with binary MiB (24.8832 MB is about 23.73 MiB).
Using 24 bits per pixel for video that is actually 4:2:0 or 10-bit.

Keep in mind: These are payload estimates only. Actual file sizes depend on container headers, metadata, row padding and compression, and real interface requirements include protocol overhead, so treat the numbers as a lower bound for raw data.

Frequently asked questions

Why is my 4K photo only a few megabytes?

Formats like JPEG, HEIC and PNG compress the pixel data. The calculator shows the size after the file is decoded into memory, not the size on disk.

How many bits per pixel does HDR video use?

HDR is usually 10 bits per channel. With full RGB that is 30 bits per pixel; with 4:2:0 subsampling it averages 15 bits per pixel.

Sources: ITU-R Recommendation BT.2020 (parameter values for UHDTV systems) · Charles Poynton, Digital Video and HD: Algorithms and Interfaces, Morgan Kaufmann

Checked 8 Nov 2026. Standard formulas and RFC/IEEE definitions, computed locally in your browser — nothing you type is sent anywhere.

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