Tablet calibration reference
iPad Pro 11-inch (M4) screen PPI
This tablet reference combines its 2420 × 1668 display, 11-inch diagonal, and estimated 264 PPI to give you a faster starting point for online-ruler calibration.
Resolution
2420 × 1668
Screen diagonal
11"
Estimated PPI
264
How the PPI reference is calculated
PPI is the diagonal pixel count divided by the physical diagonal in inches: sqrt(width² + height²) / diagonal inches. The result is rounded to the nearest whole pixel per inch.
This value is a screen specification reference, not a promise that your browser will render one CSS inch at the same physical size.
Calibrate on this device
Use the ruler in the same orientation and browser zoom that you will use for measuring. Verify the reference scale with a physical card after the estimate is applied.