Retina Image Size Calculator
Work out @1x, @2x and @3x pixel dimensions from one base size, and estimate the uncompressed size of each image. Useful when preparing assets for iOS, Android and high-DPI web displays.
How to use
- Enter the base size in points (iOS) or CSS pixels (web/Android density-independent pixels).
- Choose the colour depth that matches your image type.
- Press Calculate to see dimensions and raw size for each scale.
How it works
Retina scales multiply each dimension: @2x doubles width and height, @3x triples them. The uncompressed size is width × height × bits per pixel ÷ 8, shown in bytes before compression. PNG and JPEG files are usually much smaller because they compress data.
Frequently asked questions
Why do my exported PNG files not match this size estimate?
Because PNG applies lossless compression and JPEG applies lossy compression. The estimate shows the raw pixel data size (like an uncompressed BMP or an in-memory texture), which is useful for memory planning, not file-size planning.
What resolution do I need for Retina web images?
Export the image at @2x (or @3x for very high-density phones) and display it at CSS-pixel size. Browsers downscale automatically, which keeps the image sharp.