iPhone 13 Pro Max Screen Ruler
This page provides a ruler calibrated specifically for the iPhone 13 Pro Max. The iPhone 13 Pro Max has a 6.7-inch screen with a pixel density of 458 PPI (pixels per inch), which translates to approximately 180 pixels per centimeter. Use the ruler above to measure real-world objects directly on your iPhone 13 Pro Max screen with accuracy within 0.5mm after calibration.
The iPhone 13 Pro Max introduced ProMotion to the iPhone line, with a 6.7-inch Super Retina XDR OLED running an adaptive 120Hz refresh rate. Its LTPO panel and stainless steel frame make it one of the largest and most rigid iPhones for pressing a calibration card flat against the screen. With 458 PPI across a 2778x1284 display, on-screen ruler markings stay crisp even at the millimeter level, and the 6.7-inch diagonal gives nearly 14 cm of usable measuring length in portrait.
iPhone 13 Pro Max Display Specifications
Screen Size
6.7"
Pixel Density
458 PPI
Device Type
smartphone
Pixels per CM
180
How to Measure on Your iPhone 13 Pro Max
- Open the ruler on your iPhone 13 Pro Max using any web browser (Safari, Chrome, or Firefox all work).
- Calibrate by placing a credit card or known-size object on the screen and adjusting the calibration slider until the on-screen outline matches the object exactly.
- Measure by placing any object against the ruler markings. The ruler displays centimeters, millimeters, and inches simultaneously.
- Your calibration is saved automatically in your browser for 30 days, so the ruler stays accurate on return visits.
Why PPI Matters for Screen Measurement
PPI (Pixels Per Inch) determines how large each pixel appears on your screen. The iPhone 13 Pro Max's 458 PPI means 458 tiny dots fit within one physical inch of screen space. A higher PPI means smaller pixels, sharper text, and more precise ruler markings.
For comparison, a typical desktop monitor has around 96 PPI, while the iPhone 13 Pro Max at 458 PPI offers 4.8x the pixel density. This higher density allows the on-screen ruler to display finer graduation marks and more accurate measurements.