Image file size calculator
Type in the pixel dimensions and see roughly how big the file lands in each format. Useful before you compress something, or when you're deciding which format to save in.
This matters more than people expect. The same PNG that's a sensible size for a screenshot is one of the largest options for a photo.
Estimated file sizes
For a image. Bars are relative to the uncompressed baseline.
These are estimates, not encoder output. Real sizes move with the picture itself: a flat blue sky compresses far harder than a crowd or a forest. Treat the numbers as the right order of magnitude, then check the real thing.
Which one should you pick?
- Photos for the web: WebP, or AVIF if you want the smallest files. Both are supported in every current browser. See the best image format for web.
- Photos to send or archive: JPG. It opens on anything, and at 80-85% quality nobody can tell.
- Screenshots, logos, diagrams: PNG. A JPG of the same screenshot can come out slightly smaller, but it smears the edges of text. PNG stays sharp and costs you very little on flat color.
- Print or scanning: TIFF, or a high-quality JPG if the file has to travel.
Related tools
Actually make the file smaller: compress images on Mac
The real thing, not an estimate. Batch a whole folder down and watch the numbers.
Change the dimensions: resize images on Mac
Fewer pixels is the biggest saving there is. Resize by size, by percentage, or to a target.
Change the format: image converter for Mac
HEIC, WebP, AVIF, PNG, JPG and more. The format often matters more than the slider.
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