🖼️ Image File Size Calculator
Estimate an image’s uncompressed and compressed file size from its resolution, bit depth, and color mode.
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How image file size is estimated
An uncompressed digital image’s file size depends on how many pixels it has, how many color channels each pixel stores, and how many bits are used to represent each channel. This calculator multiplies these together to find the raw, uncompressed size, then estimates a compressed size using a typical compression ratio you provide.
Formula used: Uncompressed Size (bytes) = Width × Height × Channels × Bit Depth ÷ 8, converted to megabytes by dividing by 1,048,576.
- Grayscale images use 1 channel, standard RGB photos use 3, and images with transparency (RGBA) or print CMYK use 4.
- Real-world compressed formats like JPEG typically achieve compression ratios of roughly 10:1 to 20:1 depending on quality settings and image content; adjust the ratio field to match your target format.
This tool gives estimates for general planning purposes; actual file sizes from cameras, editors, or export tools may vary based on metadata and compression algorithm details.
Last reviewed August 2026