About this calculator

The TV Size Calculator is a free tool that helps you choose the right television size for an actual room — not just a number in the abstract. You enter how far you sit and, optionally, how wide your wall is; it returns a recommended size range and draws the TV to scale so you can see how big it really looks before you buy.

How the recommendation is made

What your eyes care about is the viewing angle — how much of your field of view the screen fills — not the diagonal alone. We use three widely cited targets:

• Comfortable — SMPTE 30°. The Society of Motion Picture and Television Engineers' reference for relaxed viewing. Diagonal ≈ distance × 0.61.
• Sweet spot — ~33°. A practical middle ground most people prefer. Diagonal ≈ distance × 0.69.
• Immersive — THX 40°. THX's recommendation for a cinema-like field of view. Diagonal ≈ distance × 0.84.

For a 16:9 screen the width is the diagonal × 0.8716 and the height is × 0.4903. The viewing angle is θ = 2 · atan( (width ⁄ 2) ÷ distance ), and we invert it to recommend a diagonal for each target angle. Resolution sets how close you can sit before pixels show: about 1.5× the screen height for 4K, 2.5× for 1080p, and 0.7× for 8K.

Our approach

We try to give an honest answer rather than push the biggest possible screen. The tool flags when a size is too large for your wall or too close for your resolution, and it suggests a sensible mounting height. All figures are estimates — always confirm exact product dimensions before buying.

How we're funded

The calculator is free to use. Some links to televisions are affiliate links: as an Amazon Associate this site may earn from qualifying purchases, at no extra cost to you. This never changes the recommendations the tool produces.

Questions or corrections? Get in touch.