Device Pixel Ratio Calculator

Device Pixel Ratio (DPR) is the ratio between physical pixels and logical CSS pixels. On Retina displays, one CSS pixel maps to 4 or 9 physical pixels, requiring higher-resolution images

The calculator uses the standard published formula for pixel ratio calc. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: DPR = Physical pixel resolution / CSS (logical) resolution. Each step in the calculation is shown so you can verify the result manually.