Screen Size Recommender
Measure the seat-to-screen distance first, then decide the screen size
The recommended screen size depends on viewing distance and target viewing angle: image width = 2 × viewing distance × tan(angle ÷ 2). For a 3 m viewing distance and a 16:9 image: about 88 inches at THX 36° (immersive), about 73 inches at SMPTE 30° (conservative), and about 63 inches at the THX minimum acceptable angle of 26°. A larger angle is more immersive but makes pixel structure and edge distortion more visible, so weigh it against your source resolution.
Viewing distance conversion
Recommended screen diagonal
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The corresponding image width is about —. When buying, round to a nearby standard size (for example 84, 100 or 120 inches) and make sure the clear wall width exceeds the image width.
The viewing angle is that subtended at the eye by the two edges of the screen; the larger the angle, the more the image fills your field of view. Viewing distance is eye to image, while throw distance is lens to image — the two are different. Use your actual throw ratio to find the throw distance →
Viewing distance and screen size reference
16:9 image; the table gives the screen diagonal (in inches) for each viewing-angle standard.
| Viewing distance | 22° broadcast TV | 26° THX minimum | 30° SMPTE | 36° THX |
|---|
Viewing-angle standards
Common horizontal viewing-angle reference values. The angle is that subtended at the eye by the two edges of the screen; the larger the angle, the more the image fills your field of view.
Comparable to the viewing angle from a center seat in a commercial THX cinema, bringing peripheral vision into the image. Suited to dedicated home cinemas.
A more conservative cinema recommendation, suited to multi-purpose rooms such as living rooms that also serve for hosting and circulation.
The minimum acceptable viewing angle given by THX. Below this the image looks noticeably small and wastes the space.
These angle values are taken from public THX and SMPTE EG-18 recommendations. Sources differ slightly in how they state the same standard; this page is for estimation and your own viewing habits should decide in the end.
FAQ
Where do I measure viewing distance from?
The straight-line distance from the viewer's eye (typically eye level when seated against the sofa back) to the screen surface. It is not the total room length or a wall-to-wall measurement. If the sofa back reclines, measure from the position you use most often.
Can I sit closer with 4K content?
Yes. The main limit on viewing distance is whether you can see the pixel structure: the practical minimum for 1080p is about 1.6× image height, and 4K can be compressed to about 1.0×. 4K therefore allows a wider viewing angle (closer, or a larger image), although edge distortion and the projector's optical quality still set limits.
At the same distance, is the recommended size the same for 4:3 and 16:9?
No. Viewing-angle standards constrain the image width, and at the same width a 4:3 image has a shorter diagonal than 16:9. Compared by diagonal, a 4:3 screen therefore shows a smaller number.
The calculated size differs from a retailer's recommendation — which should I follow?
This page gives a range based on viewing-angle standards (26°–36°), not a single answer. Retailers often lean towards larger sizes to highlight selling points. Confirm the clear wall width and mounting conditions first, then choose within this range rather than ordering by diagonal alone.