Screen Size Calculator — What Size Is My Screen?
See the size of the screen you're using now, or work out width, height and PPI from any diagonal.
Your screen
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Screen size calculator
Screen size is measured diagonally across the visible screen, corner to corner, without the frame.
How screen size is measured
Screens are sold by their diagonal: the distance from one corner of the visible picture to the opposite corner, without the frame. Width and height depend on the shape, or aspect ratio. Most TVs and monitors are 16:9, many laptops are 16:10 or 3:2, and phones are about 19.5:9. The calculator uses Pythagoras: width² + height² = diagonal².
Related guides: How to Measure a TV or Monitor Screen Size · How to Show the Ruler in PowerPoint
How to use it
- To see your own screen, tap Calibrate first so the page knows your pixel density.
- To size another screen, enter its diagonal and pick its aspect ratio, or switch to width and height.
- Add the resolution to get its pixel density (PPI) and the size of one pixel.
Good to know
- A 16:9 screen is 87.2% of its diagonal wide and 49.0% of it tall.
- At the same diagonal, a 4:3 screen has 12% more area than a 16:9 one, and a 16:9 screen has 18% more than an ultrawide 21:9.
- TVs are often sold by size class: a "65-inch class" TV can measure 64.5 inches diagonally.
- Pixel density (PPI) = √(horizontal px² + vertical px²) ÷ diagonal in inches.
TV screen sizes: width and height (16:9)
The visible screen of a 16:9 TV, calculated from its diagonal. Add a few centimeters for the frame when you check whether a TV fits a space.
| TV size (diagonal) | Width | Height |
|---|---|---|
| 32″ | 27.9 in (70.8 cm) | 15.7 in (39.8 cm) |
| 40″ | 34.9 in (88.6 cm) | 19.6 in (49.8 cm) |
| 43″ | 37.5 in (95.2 cm) | 21.1 in (53.5 cm) |
| 50″ | 43.6 in (110.7 cm) | 24.5 in (62.3 cm) |
| 55″ | 47.9 in (121.8 cm) | 27.0 in (68.5 cm) |
| 65″ | 56.7 in (143.9 cm) | 31.9 in (80.9 cm) |
| 75″ | 65.4 in (166.0 cm) | 36.8 in (93.4 cm) |
| 85″ | 74.1 in (188.2 cm) | 41.7 in (105.8 cm) |
| 98″ | 85.4 in (217.0 cm) | 48.0 in (122.0 cm) |
- Monitors use the same maths: a 24″ 16:9 monitor is 20.9 × 11.8 in, a 27″ one is 23.5 × 13.2 in, and a 34″ 21:9 ultrawide is 31.3 × 13.4 in.
- Laptops: a 14″ 16:10 screen is 11.9 × 7.4 in; a 15.6″ 16:9 screen is 13.6 × 7.6 in.
- For wall mounting or a TV cabinet, use the maker's outer dimensions, which include the frame.
Three ways to calibrate
Auto-detect your device
The ruler recognizes about 130 phones, tablets, laptops and monitors, including iPhones, Galaxy phones, Pixels and MacBooks.
Enter your screen size
Enter your screen's diagonal size (for example, 15.6" for a laptop), and the ruler works out the scale from your screen resolution.
Calibrate with a bank card
Hold any bank card against the outline on screen and move the slider until they match. Bank cards are the same size everywhere: 85.60 × 53.98 mm.
How accurate is the ruler?
How accurate the ruler is depends on how well it knows your screen's pixel density, meaning how many pixels fit in an inch. There are three ways to set it, from most to least accurate:
Bank card (±0.5%): Bank and credit cards are made to one worldwide size, 85.60 × 53.98 mm (ISO/IEC 7810 ID-1). Because every card is exactly the same, matching one on screen gives the most accurate result.
Auto-detect (±1%): The ruler looks up your device's published screen size and resolution. Screens of the same model can differ very slightly, so this is a little less exact. It covers about 130 devices.
Screen size (±2%): You type in your screen size, and the ruler works out the rest from your resolution. Advertised sizes are rounded (a "15.6-inch" screen may really be 15.59 inches), so this is the least exact method. It's a good fallback when you don't have a card.
Real-life objects to check your measurements
Use these everyday objects to confirm the ruler is calibrated correctly.
Bank or credit card: 85.60 × 53.98 mm (3.37 × 2.13 in)
A4 paper: 210 × 297 mm (8.27 × 11.69 in)
US Letter paper: 8.5 × 11 in (215.9 × 279.4 mm)
US quarter: 24.26 mm (0.955 in) across
1 euro coin: 23.25 mm (0.915 in) across
AA battery: about 50.5 mm long and 14.5 mm wide