Screen Size Calculator
Enter the diagonal size of a TV, monitor or projector screen and pick its aspect ratio and resolution. You get the real width and height, the pixel density and how far to sit.
- Any aspect ratio
- Pixel density
- Viewing distance
Sizes are for the visible picture. Add the bezel or frame when checking whether it fits a space.
The diagonal hides the shape. A 34 inch ultrawide monitor and a 34 inch 16:9 monitor have the same diagonal but very different heights. The ultrawide is about 13.4 inches tall and the 16:9 screen is 16.7 inches. Width and height tell you whether a screen fits your desk or wall.
Common screen sizes
Width and height of popular 16:9 sizes. Search for a diagonal or a measurement.
| Diagonal | Width (in) | Height (in) | Width (cm) | Height (cm) |
|---|---|---|---|---|
| 24 in | 20.9 | 11.8 | 53.1 | 29.9 |
| 27 in | 23.5 | 13.2 | 59.8 | 33.6 |
| 32 in | 27.9 | 15.7 | 70.8 | 39.8 |
| 43 in | 37.5 | 21.1 | 95.2 | 53.5 |
| 50 in | 43.6 | 24.5 | 110.7 | 62.3 |
| 55 in | 47.9 | 27 | 121.8 | 68.5 |
| 65 in | 56.7 | 31.9 | 143.9 | 80.9 |
| 75 in | 65.4 | 36.8 | 166 | 93.4 |
| 85 in | 74.1 | 41.7 | 188.2 | 105.8 |
| 100 in | 87.2 | 49 | 221.4 | 124.5 |
Real TVs add 1 to 3 cm of bezel on each side. Check the maker's spec sheet for the exact outer size if it has to fit a cabinet or alcove.
How the diagonal scales
A 16:9 screen at any size. Slide the diagonal to see width, height and seating distance.
Screen area grows with the square of the diagonal. A 65 inch TV has 40% more picture than a 55 inch, not 18% more, which is why the jump feels so large in a room.
How to measure a screen
Screen sizes are always measured corner to corner. Use a tape measure and these steps.
Find opposite corners
Use the bottom left and top right of the visible picture.
If the result is a little smaller than the advertised size, that is normal. Makers round to the nearest whole inch.
Choosing an aspect ratio
Shape changes what the screen is good for. Compare common ratios.
The standard for TVs, streaming and most monitors.
Ultrawide monitors give more horizontal space for timelines, spreadsheets and racing games.
A little taller than 16:9. Common on laptops and good for reading documents.
Films shot in 2.39:1 show black bars on a 16:9 TV. On an ultrawide monitor they fill most of the screen, but normal TV shows get bars on the sides instead.
Before you buy a screen
Check the space and the seat. Tick each item.
Tick each item as you go.
For wall mounting, the centre of the screen should sit at about eye level when seated, which is roughly 100 to 110 cm from the floor for a sofa.
What the result shows
The numbers you need to plan a screen. Each tile explains one result.
The real picture size in inches and centimetres.
Useful for comparing two sizes fairly.
Pixels per inch for your resolution.
Based on a 40° viewing angle.
Where single pixels stop being visible.
Pixel density tells you how sharp text will look. Desktop monitors look crisp from about 100 PPI at arm's length; phones need 300 PPI or more because you hold them close.
Frequently Asked Questions
No question matches that search.
How wide is a 55 inch TV?
The picture is about 47.9 inches (121.8 cm) wide and 27 inches (68.5 cm) tall. With bezels, most 55 inch TVs are about 123 cm wide.
How do I calculate screen width from the diagonal?
For 16:9, width = diagonal × 0.8716 and height = diagonal × 0.4903. Other ratios use the same idea with their own numbers.
How far should I sit from a TV?
About 1.2 to 1.6 times the diagonal for a 4K TV. That is 1.7 to 2.2 m for a 55 inch set.
What PPI is good for a monitor?
About 100 to 110 PPI is comfortable on a desk. 27 inch 1440p gives 109 PPI and 27 inch 4K gives 163 PPI.
Is screen size measured with or without the bezel?
Without. The size is the diagonal of the visible picture.
What is the difference between 21:9 and 16:9?
21:9 is wider and shorter. A 34 inch 21:9 monitor is about as tall as a 27 inch 16:9 screen but 30% wider.
How do I measure a projector screen?
The same way, diagonally across the visible area. Projector screens are often 16:9 or 2.35:1.
Know the real size before you buy
Use the diagonal and ratio to get the true width and height, then check it fits the space with the bezel and stand added. Match the resolution to the size and seat distance, and the picture will look sharp from where you actually sit.
More size calculators
Each one has its own calculator, worked examples and answers to common questions.