Screen Size vs Watching Distance Chart
Here is a chart with the flat screen size vs watching distance.
The distances are quite a wide range and this is because you need to sit at a different distance depending on the quality of the picture.
For high definition 1080p go for the lowest end of the scale and sit as close as possible to get full advantage of the great picture. For high definition 720p go for the low to medium end of the scale and sit slightly further away. For standard definition sit closer to the top end of the scale, if the picture quality is poor then it is better to sit further away from the screen.
•26 Inch – 3.2 feet to 8 feet
•30 Inch – 3.8 feet to 10 feet
•32 Inch – 4.2 feet to 11 feet
•34 Inch – 4.4 feet to 12 feet
•40 Inch – 5 feet to 14 feet
•42 Inch – 5.5 feet to 15 feet
•46 Inch – 6 feet to 16.5 feet
•50 Inch – 6.5 feet to 17.5 feet
•55 Inch – 7 feet to 19 feet
•60 Inch – 7.5 feet to 21 feet
•63 Inch – 8 feet to 22 feet
•65 Inch – 8.5 feet to 23 feet