How to Use the Phone Screen Size Calculator
A phone spec sheet listing '6.1 inches' only tells you the diagonal screen measurement — not the actual width and height you'll hold in your hand. Two phones with the same diagonal size can feel very different if their aspect ratios differ.
Enter the diagonal screen size in inches and select the aspect ratio, and this tool uses the Pythagorean theorem to calculate the actual width and height in both millimeters and inches. Choose from common ratios like 19.5:9 and 20:9 used on modern phones, older 16:9, tablet-style 4:3, or enter a custom ratio.
Use this before buying a case, mount, or screen protector without measuring the phone in person, to compare how different models will feel in your hand, or to check whether a phone fits inside a waterproof pouch or car mount. Note that bezel thickness isn't included, so the total device size may be slightly larger than the screen dimensions shown here.
Frequently Asked Questions
No — this calculator only accounts for the display's diagonal size, so the phone's total physical dimensions (including the bezel) may be slightly larger than the numbers shown here.
Check the manufacturer's official spec sheet for 'Aspect Ratio.' If you can't find it, select 'Custom' and enter the screen resolution (width x height in pixels) instead — the ratio works the same way.