Optimal HDTV Size and Viewing Distances

It is easy to get caught up in TV specifications and forget that unless your viewing distance is optimal and your vision is 20/20, then you will not see the best possible picture that you have paid so much money for.

The Economist published an interesting article about HDTV buying in which they discuss the limits of human vision, reminding us that the eye cannot resolve spatial patterns beyond a certain distance.

The article goes on to state that most people sit too far back from their TV. If you sit 9 feet (2.74 meters) back from your 1080p HDTV, then you’ll need at least a 69-inch (175.26 cm) TV, measured diagonally, to see all of the detail you’ve paid for. Any other combination of greater distance or smaller screen size means you will not be able to resolve the finer details.

The article is based on the research of Bernard J. Lechner, formerly an electronics engineer and VP at RCA Laboratories. He developed two simple formulas for calculating optimum viewing distances for 16×9 HDTVs based on visual acuity.

Optimal Viewing Distance for 16×9 1080p HDTV = 1.8 x Width
Optimal Viewing Distance for 16×9  720p HDTV = 2.7 x Width

Knowing your TV width is somewhat tricky, since all TV sizes are expressed in diagonal measurements. Of course you can always get out that tape measure, or calculate it. For 16×9 sets, width is easy to calculate since you probably know the diagonal screen size.

Width = 0.871575537124549 x Diagonal Size

In lieu of breaking out that calculator just yet, use the table below to see the optimal viewing distances for common screen sizes. You may be surprised just how much closer you should be sitting to the TV.

Optimal Viewing Distances for 16×9 HDTV Screen Sizes

Diagonal (inches)	Width (inches)	Height (inches)	1080p Optimal Viewing Distance (width x 1.8) (feet)	720p Optimal Viewing Distance (width x 2.7) (feet)
80	69.73	39.22	10.46	15.69
70	61.01	34.32	9.15	13.73
60	52.29	29.42	7.84	11.77
55	47.94	26.96	7.19	10.79
50	43.58	24.51	6.54	9.81
46	40.09	22.55	6.01	9.02
42	36.61	20.59	5.49	8.24
32	27.89	15.69	4.18	6.28

If you’re buying a new HDTV, use these calculations to help you choose the perfect sized TV for your room. If you’re viewing distance is like most people at 9 feet, then your best bang for the buck would be a 46-inch 720p HDTV. However, those 720p sets are harder and harder to find since just about every new model is now 1080p. So buy the biggest TV you can afford and place optimally, otherwise you just won’t be able to tell the difference.

2016 Update:
If you buy a 4K Ultra HD TV you can sit a little closer to the TV. However, since such limited content is available in 4K, you’ll likely be watching in 1080p or less resolution most of the time. So I’d still recommend the 1080p optimal distance recommendations.

Related:
Optimum HDTV viewing distance (Wikipedia)
1080p and HDTV Resolution Explained (eCoustics)