How to use the retina @2x and @3x resolution calculator
On high-density displays the logical px your CSS works in and the physical px the panel actually lights up are not the same number. To fill a 375 by 812 slot without softness, the image has to be exported larger than the slot. Enter the logical width and height and this page returns the real export dimensions at @1x, @2x and @3x, along with total pixel counts and how each one compares to @1x.
The arithmetic is plain: export width equals logical width times the scale, height works the same way, and the pixel count is the product of the two. That is why @2x holds four times the pixels and @3x nine times — doubling a length quadruples an area. It also explains why file weight grows far faster than the scale number suggests (checked October 2026; the scale factors an operating system exposes can change with its display settings).
If you lay out on half-pixel values, @3x lands on a fractional px, and a separate warning line appears when that happens. This tool does not write srcset or sizes markup and does not convert image files. It also does not list which device runs at which scale, so decide the scales you need to support yourself.
Frequently asked questions
No. Both width and height double, so the pixel count is four times larger. The 'vs @1x' column shows that ratio. Actual bytes then depend on your format and compression settings.
It will not. This page calculates export dimensions only. Responsive markup is handled by a separate tool, so this one stays focused on planning sizes.
Your logical size sits on a half pixel, so multiplying by the scale leaves a remainder. Exporting that way straddles a pixel boundary and softens edges, so round the logical size to whole numbers.