TV Size Calculator: What Size TV for My Room?
Find the best TV size for how far you sit from the screen, or the best distance for the TV you already have. See the screen's real width and height in cm, how it looks on your wall, and how high to mount it.
No sign-up required. Free to use, with every formula shown on this page. Last reviewed October 2026.
Find your TV size
TV Size & Viewing Distance Calculator
Find the best TV size for how far you sit from it, or the best distance for the TV you already have. See how wide and tall the screen really is, and how high to mount it.
1 What do you know?
Measure from where your head is on the sofa to the wall or unit the TV goes on.
2 How you watch
How big should it feel? Picture qualityAlmost every TV over 43 inches sold today is 4K. HD matters if you mostly watch older channels or DVDs: sit too close and you see the picture's dots.
3 Your room (optional)
Space: between alcoves, or the width of the unit. Eye height: about 100 to 110 cm from the floor on most sofas.
Best TV size
Screen, width × height
Fills your view by
Screen centre at
Your wall, to scale
Every common size
| Size | Screen | Sit | From you |
|---|
How it's worked out: TV sizes are the diagonal of a 16:9 screen, so the width is 0,872 × the diagonal and the height 0,49 ×. How much of your view the screen fills is the angle between its two edges seen from your seat: the cinema setting aims for 40° (the THX guideline), balanced for 30° (the SMPTE guideline) and relaxed for 20°. The closest distance also keeps the picture's dots too small to see with normal eyesight (one minute of arc): about 0,9 × the screen width for 4K and 1,8 × for HD. The screen centre goes at your seated eye height.
A guide, not a rule. Real TVs are a little bigger than the screen because of the frame, and stand widths vary: check the maker's measurements before you buy.
How it works
It's about how much of your view it fills
A TV that looks huge in the shop can look small from the sofa. What matters is the angle the screen takes up from where you sit. The sources and assumptions behind it are on our How we calculate page.
Viewing angle
Film-industry guidelines aim for the screen to fill about 30° of your view (SMPTE), or 40° for a cinema feel (THX). Under 20° and the picture starts to feel small. The calculator turns your distance into the screen width that gives each angle.
Picture quality
Sit too close and you can see the picture's dots. With normal eyesight that's closer than about 0.9 times the screen width for 4K, and 1.8 times for HD, which is why 4K lets you sit nearer or buy bigger.
Inches to centimetres
TV sizes are the diagonal in inches. A 16:9 screen is 0.87 times the diagonal wide and 0.49 times high: a 55 inch TV is about 122 × 68 cm, before the frame and stand.
Examples
What size TV for your viewing distance?
The best 4K TV size for common seating distances, worked out with the calculator above.
4K picture. "Sizes that work" fill between 20° and 40° of your view. For an HD TV, sit further back or choose a smaller size.
Tips
Getting the TV right in the room
Size is only part of it. Where and how high it goes matter just as much.
Mount it at eye level
The centre of the screen should be about level with your eyes when you sit, usually 100 to 110 cm from the floor. Over a fireplace is often too high; if it must go there, use a bracket that tilts it down.
Check the space
Measure the gap between alcoves or the width of the unit, and allow a few cm for the frame. The calculator greys out sizes that won't fit and draws the TV on your wall to scale.
Bigger costs more to run
A larger screen uses more electricity, and some of the new very bright TVs use a lot. Check what yours costs a year with the Electricity Cost Calculator.
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Common questions
Frequently asked questions about TV size and viewing distance
Common questions about choosing a TV size, viewing distance and mounting height.
What size TV should I get for my room?
Measure from your eyes to where the screen will be. From 2 metres a 50 inch 4K TV suits most people, from 2.5 metres a 65 inch, and from 3 metres a 75 inch. If you want a cinema feel for films and sport, go one size up.
How far should I sit from a 55 inch TV?
About 2.3 metres for a balanced view, and anywhere from 1.7 to 3.5 metres works for a 4K set. For an HD set, sit at least 2.2 metres away or you'll see the picture's dots.
How far should I sit from a 65 inch TV?
About 2.7 metres for a balanced view, and anywhere from 2.0 to 4.1 metres works for a 4K set.
How do I measure a TV size?
TV sizes are measured corner to corner across the screen, in inches, without the frame. To get the width of a 16:9 screen in cm, multiply the size by 2.21; for the height, by 1.25. A 55 inch TV is about 122 cm wide and 68 cm high.
How high should I mount my TV?
Put the centre of the screen at your eye height when you're sitting down, usually about 100 to 110 cm from the floor. For a 55 inch TV that puts the bottom edge about 70 cm and the top about 140 cm from the floor.
Is a bigger TV always better?
Not if you sit close. Once the screen fills more than about 40° of your view you have to move your eyes and head to follow the picture, and with an HD set you'll see the dots. Within the range the calculator gives, bigger is usually nicer.
Does 4K let me sit closer?
Yes. A 4K picture has four times the dots of HD, so you can sit about half as far away before you notice them. That's why a big 4K TV works in a normal living room.