TV Size Calculator
The right screen for your sofa, and the width it needs.
TV Size Calculator turns a viewing distance into a screen size and back again, using the SMPTE 30 degree and THX 36 to 40 degree viewing angles, for 4K and 1080p. It also gives the real width and height behind a 16:9 diagonal, since a diagonal alone will not tell you whether it fits. Nothing is uploaded.
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Runs entirely on your device. No file or text you enter here is uploaded. How to verify it.
How to use TV Size Calculator
- Choose whether you know the distance or the screen size.
- Enter the figure, the aspect ratio and the resolution.
- Read the recommended range, the panel's real width and height, and the resolution limit.
Questions about TV Size Calculator
Where do the 30 and 40 degree figures come from?
SMPTE specifies a 30 degree horizontal viewing angle for a reference viewing environment — the conditions a film is judged in. THX describes 36 to 40 degrees for a dedicated cinema room, with 40 as the maximum before the eye has to travel across the frame. They are recommendations for watching film attentively, not rules about eyesight or comfort.
Why does it suggest a bigger television than my living room can take?
Because both standards come from rooms built for watching films and nothing else. Most sofas sit well beyond the THX range, and that is a perfectly reasonable choice for a room where you also read, talk and eat. Use the table of real sizes to see the angle each one would give you and pick from that instead of from the recommendation.
Can I actually see the difference between 4K and 1080p?
Only within a certain distance, and the tool works it out. A 20/20 eye resolves about one arcminute, so a 4K picture stops revealing extra detail beyond roughly 1.6 times the screen height — about 1.3 metres for a 65 inch set. Past that the same picture at half the resolution would look identical. That is an argument against paying for 8K, not against 4K panels, which are now what is sold anyway.
Why does it show the width and height as well?
Because a diagonal is a poor description of a screen. The same 55 inches is shared between width and height differently at 16:9 and 21:9, so two sets sold at the same size can differ by more than 20 centimetres across. Measure your wall or cabinet against the width, not against the advertised number.
Does the size include the frame and the stand?
No. The diagonal a manufacturer prints covers the picture area only. Add roughly one to three centimetres of bezel on each side for the whole set, and check the stand's own footprint separately — it is often wider than people expect and it decides whether the set fits a cabinet at all.
Is TV Size Calculator really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use TV Size Calculator?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.