The Pixel Math

This image file size calculator computes the raw bitmapped size — width × height × bits per pixel ÷ 8 — then divides by a compression ratio to estimate JPEG-style file sizes. Every pixel stores its color in bits: 24 for full RGB, 32 with alpha, 8 for grayscale.

Why Compression Matters

A 12 MP camera frame is 36 MB raw. JPEG typically reaches 10–20:1 by discarding high-frequency detail the eye barely notices, dropping the file to a few megabytes — the trade-off between quality and size that every photographer manages.

Planning Storage and Bandwidth

Multiply the compressed size by your image count to size CDN, cache, and hosting budgets. For lossless needs, subtract the compression ratio and accept the larger files — PNG and RAW exist precisely because some content can't afford loss.