Arm's Length From the Screen: Guidance Puts Monitor Distance at 20 to 28 Inches
Engadget guidance says a monitor should sit roughly an arm's length from the eyes, about 20 to 28 inches, with the distance growing for larger displays and height and tilt adjusted to eye level.
The publication describes the arm's length rule as the simplest way to set the distance: stretch out an arm and place the monitor so the fingertips just reach the screen. The recommended 20 to 28 inch range for the eyes lines up with the upper end of that measurement, since the average adult arm is about 28 to 31 inches long. Keeping a display at that distance is intended to prevent eye strain and fatigue, while also discouraging the forward leaning that Engadget says can aggravate the neck and back and encourage poor posture.
Specific distances vary by screen size. The Occupational Safety and Health Administration recommends keeping a 24-inch display about 20 to 28 inches away, according to the report. For a 27-inch monitor, that distance should increase to 24 to 32 inches. Displays of 32 inches and larger require more separation still, so that the whole screen stays within the user's field of view without constant neck movement; Engadget puts a comfortable position at 34 to 38 inches. Resolution matters at those sizes, the report says, because higher pixel counts allow a user to sit closer before individual pixels become visible, which is why many 32-inch monitors are at least 1440p.
Laptop screens are smaller, and the report recommends adding a separate keyboard and mouse so the user can keep the arm's length distance while still typing comfortably. Depending on eyesight, larger font sizes or increased screen scaling may also be needed.
Height and tilt matter alongside distance. The monitor should face the user directly and sit at eye level, with the top of the screen at or slightly below eye level and the middle of the screen 15 to 20 degrees below it. Laptop viewing angles are commonly too low, the report notes. A height-adjustable chair or desk, or an accessory such as a laptop riser, can bring the display into position, and the chair should be set so the feet remain flat on the floor.
Users who wear bifocals, which require looking through the bottom portion of the lens for close work, should lower the monitor a little further. The screen should be tilted back 10 to 20 degrees, or as much as 30 to 45 degrees for bifocal wearers. Brightness should be adjusted so it is not overly intense, and an anti-glare filter can be added if the monitor does not include that technology.
Engadget states that the same rules apply to multi-monitor setups.