Screen Size Calculator
Enter your screen's diagonal size and aspect ratio to get its exact width and height in cm, mm, and inches. Works for TVs, monitors, laptops, phones, and tablets.
Common Screen Sizes
| Device | Diagonal | Ratio | Width (cm) | Height (cm) |
|---|---|---|---|---|
| 13.6" MacBook Air M2 | 13.6" | 16:10 | 30.0 | 18.8 |
| 14" MacBook Pro M3 | 14.2" | 16:10 | 31.3 | 19.6 |
| 15.6" Laptop (FHD) | 15.6" | 16:9 | 34.5 | 19.4 |
| 24" Monitor (FHD) | 23.8" | 16:9 | 52.7 | 29.6 |
| 27" Monitor (QHD) | 27" | 16:9 | 59.8 | 33.6 |
| 32" Monitor (4K) | 31.5" | 16:9 | 69.8 | 39.2 |
| 43" TV | 43" | 16:9 | 95.2 | 53.5 |
| 55" TV | 55" | 16:9 | 121.8 | 68.5 |
| 65" TV | 65" | 16:9 | 143.9 | 80.9 |
| iPhone 15 (6.1") | 6.1" | 19.5:9 | 7.2 | 14.7 |
| iPhone 15 Pro Max (6.7") | 6.7" | 19.5:9 | 7.7 | 16.6 |
| iPad Air 11" | 11" | 4:3 | 22.0 | 16.5 |
| Samsung Galaxy S24 | 6.2" | 19.5:9 | 7.1 | 15.1 |
Frequently Asked Questions
How do I calculate screen width and height from diagonal size?
Use the aspect ratio to find the proportions. For a 16:9 screen: width = diagonal × 16 / √(16² + 9²) = diagonal × 0.8723. Height = diagonal × 9 / √(16² + 9²) = diagonal × 0.4907. For example, a 27" 16:9 monitor is 23.5" wide × 13.2" tall (59.8 × 33.6 cm).
How big is a 27 inch monitor in cm?
A 27" monitor with a 16:9 aspect ratio is approximately 59.8 cm wide × 33.6 cm tall. The diagonal (27 inches) measures the corner-to-corner distance of the screen. The actual usable dimensions depend on the aspect ratio.
How big is a 55 inch TV in cm?
A 55" TV with 16:9 aspect ratio is approximately 121.8 cm wide × 68.5 cm tall. In inches: 47.9" × 27.0". Add about 2–4 cm per side for the bezel when measuring total set dimensions.
What is aspect ratio?
16:9 is the most common TV and monitor ratio — 16 units wide for every 9 units tall. 16:10 is used on many MacBooks and productivity monitors (slightly taller). 4:3 was the old standard, now mainly iPads. 21:9 is ultrawide. The ratio tells you the screen's shape, not its size.
How do I find my screen size?
Measure diagonally from one corner of the screen to the opposite corner (not including the bezel). On a laptop or phone, the spec is printed on the box or in System Settings → About. On a monitor, it's in the product name or manual.
Does screen size include the bezel?
No — screen size refers to the active display area only, measured diagonally. The bezel (the frame around the screen) is not included. So a "27 inch monitor" has a 27-inch diagonal display, but the total physical unit is larger.
How big is a 13 inch laptop screen in cm?
A 13" laptop with 16:10 aspect ratio (e.g. MacBook Air) has a screen approximately 28.0 cm wide × 17.5 cm tall. A 13" 16:9 laptop is 28.7 cm × 16.2 cm. The exact size depends on the aspect ratio.
What is the actual size of an iPhone screen?
iPhone 15 (6.1"): approximately 7.2 cm wide × 14.7 cm tall. iPhone 15 Pro Max (6.7"): 7.7 cm × 16.6 cm. These are the display area measurements; the physical phone body is larger due to the frame.