The screen of a 70-inch television with a modern 16:9 widescreen aspect ratio is 61.01 inches wide and 43.32 inches high. An older style 4:3 ratio screen is 56 inches wide and 42 inches high.
The standard measurement of a TV screen is given diagonally from corner to corner. GlobalRPH.com offers an online calculator to estimate the screen size and physical dimensions for televisions. Users can enter the diagonal screen size and the screen aspect ratio, and the calculator determines the measurements of the screen. The TV frame size can also be included to calculate the approximate external dimensions of the TV set.