Width = diagonal × cos(θ), height = diagonal × sin(θ), where θ = atan(aspect height ÷ aspect width).
Physical dimensions
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Why size maths matters
The diagonal alone doesn't tell you how much room a screen takes up.
Desk fit
A 32" ultrawide is far shorter than a 32" 4:3 — know the footprint before you buy.
Viewing area
Going from 55" to 65" adds over 38% more picture area, not 18%.
Viewing distance
For TVs, distance ≈ 1.5–2.5× the diagonal. For monitors, about arm's length.
Distance recommendations
Comfortable viewing distances for common TV sizes:
- • 55" TV — sit 2.1–3.5 m (7–11.5 ft) away for 1080p; closer is fine for 4K.
- • 65" TV — 2.5–4.1 m (8–13.5 ft).
- • 75" TV — 2.9–4.7 m (9.5–15.5 ft).
- • Projectors — throw ratio × screen width gives the required projector distance.
More tech tools
Check your display's pixel density with our PPI calculator.
PPI Calculator