Screen Size Calculator
Calculate exact physical screen dimensions (width, height, area, and diagonal) from aspect ratio and diagonal size, or solve for missing screen dimensions.
Calculate Screen Dimensions
Diagonal² = Width² + Height²How to Calculate Screen Dimensions
Display screens are advertised by their diagonal measurement in inches. To find the real-world physical width and height for your desk or TV wall mount, you need both the diagonal and the aspect ratio.
Screen Size Formulas
Common Screen Sizes at a Glance (16:9 Widescreen)
| Diagonal | Width (in / cm) | Height (in / cm) | Area (sq in / cm²) |
|---|---|---|---|
| 24″ (16:9) | 20.9″ (53.1 cm) | 11.8″ (29.9 cm) | 246 sq in (1,588 cm²) |
| 27″ (16:9) | 23.5″ (59.8 cm) | 13.2″ (33.6 cm) | 312 sq in (2,010 cm²) |
| 32″ (16:9) | 27.9″ (70.8 cm) | 15.7″ (39.8 cm) | 438 sq in (2,823 cm²) |
| 34″ Ultrawide (21:9) | 31.4″ (79.7 cm) | 13.4″ (34.1 cm) | 421 sq in (2,718 cm²) |
| 55″ TV (16:9) | 47.9″ (121.8 cm) | 27.0″ (68.5 cm) | 1,293 sq in (8,343 cm²) |
| 65″ TV (16:9) | 56.7″ (143.9 cm) | 31.9″ (80.9 cm) | 1,805 sq in (11,644 cm²) |
Frequently Asked Questions
How is screen size measured?
Screen size is measured diagonally from one viewable corner to the opposite viewable corner, excluding bezels and frames. A '27-inch monitor' has a 27-inch diagonal, not 27 inches of physical width.
How do you calculate screen width and height from diagonal?
Using the Pythagorean theorem with aspect ratio: Width = Diagonal × (Aspect_W ÷ √(Aspect_W² + Aspect_H²)) and Height = Diagonal × (Aspect_H ÷ √(Aspect_W² + Aspect_H²)). For standard 16:9 widescreen, Width ≈ 0.8716 × Diagonal and Height ≈ 0.4903 × Diagonal.
Why does aspect ratio affect screen area?
A screen with a squarer aspect ratio (e.g. 4:3 or 16:10) has significantly more surface area than an elongated screen (e.g. 21:9 or 32:9) with the same diagonal measurement. A 27″ 16:9 screen has ~311.5 sq inches, while a 27″ 21:9 screen has only ~284 sq inches.
Is a 34″ ultrawide taller than a 27″ standard monitor?
A 34″ 21:9 ultrawide has almost the exact same physical height (~13.2 inches) as a standard 27″ 16:9 monitor, but it extends about 7.5 inches wider on the sides.
How do I convert screen measurements from inches to cm?
Multiply inches by 2.54 to get centimeters (1 inch = 2.54 cm). For area, multiply square inches by 6.4516 to get square centimeters.