Adjust in 'Pixels Per Inch' until the line on the bottom is one inch long. Offest allows the ruler to go off-screen so you can easily compare it to a physical ruler. Using TurboWarp with HQ-pen is recommended: https://turbowarp.org/715020471 Thanks to @-rex- for SFEplus Pixels Per Inch (PPI) may not be the actual PPI of the screen, depending on the size of the project