Image File Size Calculator
Estimate uncompressed image storage from dimensions and color depth
Uncompressed size
How we calculated it
About the Image File Size Calculator
Image File Size Calculator estimates the storage required for an uncompressed image from pixel dimensions, color depth and channel count, or helps compare that raw size with a compressed file.
JPEG, PNG, WebP and other formats can produce very different file sizes because compression depends on image content, quality settings and encoding method. A raw mathematical estimate should therefore not be mistaken for an exact compressed-file prediction.
How to Use the Image File Size Calculator
- Enter image width and height in pixels.
- Enter bits per pixel or channel configuration.
- Calculate uncompressed size.
- If estimating a compressed file, enter or test a compression ratio separately rather than assuming one universal percentage.
How the Calculation Works
Uncompressed bits = width × height × bits per pixel.
Bytes = bits ÷8, then the result can be converted to KB, MB or MiB using the selected unit convention. Compressed size can be approximated as uncompressed size ÷ compression ratio when a realistic ratio is known.
Worked example
Image File Size Calculator Worked Example
4000×3000 image at 24 bits per pixel
Pixels = 12,000,000. Raw bits = 12,000,000×24 = 288,000,000 bits, or 36,000,000 bytes before compression.
Result guide
Understanding Your Image File Size Calculator Result
The raw size reflects stored pixel data without compression or file-format overhead. A real JPEG may be much smaller, while a lossless format may remain relatively large.
Before you rely on the answer
Assumptions and Limitations
- Pixel dimensions are correct.
- Bit depth or bytes per pixel are interpreted consistently.
- Compression ratio, when used, is treated as an estimate.
Practical tip
Using This Result in Practice
If you are budgeting storage for many images, test several representative files from the actual camera or workflow. Highly detailed images often compress differently from simple graphics.
Related calculations
Useful Calculations to Continue With
If you know original and compressed sizes and want the compression ratio, use the File Compression Ratio Calculator.
Pixel Density (PPI) Calculator — If you want to relate those pixels to physical display size, use the Pixel Density Calculator.
Common questions
Image File Size Calculator FAQ
How do I estimate uncompressed image size?
Multiply pixel count by bits per pixel, then divide by eight for bytes.
Why is my JPEG much smaller than the calculated raw size?
JPEG uses compression, while the raw estimate stores every pixel value directly.
Can this predict PNG size exactly?
No. Lossless compression depends on the actual image content.