Television Screen Size and Distance Calculator

The maximum viewing distance from a television screen is proportional to the size of the screen, which is most often given by the diagonal length. If you know your TV screen's diagonal length in inches or centimeters, you can plug this number into a simple formula that tells you how far away you should sit when watching TV.

Likewise, for a given distance between couch and television, you can determine the minimum screen size needed to watch TV comfortably.

You can use the formulas and example computations below, or use the handy screen size and distance calculator on the left. Click the radio button for quantity you know, enter its value with the correct units, then hit the "Calculate Distance or Size" button. Answers are only approximations and your personal preferences may vary.

Note: You can also use this viewing distance calculator to find the best placement for your TV in accordance with THX, SMPTE, and visual acuity guidelines.

Maximum Viewing Distance for a Given Screen Size

Given a screen diagonal length of L units, the maximum recommended viewing distance is about 2.5L units. For a television with an aspect ratio of 16:9 (widescreen), the maximum is slightly higher; for a TV whose aspect ratio is 4:3, the maximum is slightly lower.

Example: Julia buys a new 36" television. The maximum recommended viewing distance is (2.5)(36") = 90 inches or 7'6" (2.29 meters).

Minimum Screen Size for a Given Viewing Distance

Given a couch-to-TV distance of D units, the minimum recommended screen diagonal length is about D/2.5.

Example: Mark arranges his living room so that the couch is 2 meters from the TV stand. Since 2/2.5 = 0.8, he should buy a television with a diagonal length of 0.8 m or 80 cm (31.5 inches).

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