Image Size Calculator
Find dimensions for a target megapixel count, scale an image and see its raw memory.
Runs entirely in your browser. Nothing you type is uploaded.
About this tool
Work either way: give a ratio and a megapixel target to get dimensions, or give explicit sides. Both modes report the simplified ratio, the pixel count and the uncompressed RGB and RGBA memory, and a scaler converts to a target width, height or long edge.
Questions & answers
- Why snap dimensions to a multiple?
- Many image models work in latent blocks and want each side to be a multiple of 8, 16 or 64. Snapping avoids the model silently cropping or padding your request.
- What is the raw memory figure?
- The uncompressed pixel buffer: width × height × 3 bytes for RGB, or × 4 for RGBA. A PNG or JPEG file on disk is much smaller because it is compressed.
- Does scaling to the long edge keep the ratio?
- Yes. Whichever side is longer becomes the target and the other is scaled proportionally, so the composition is unchanged.