For basic reading, such as headlines, prices and simple graphics, the smallest character should be at least the viewing distance divided by 200, which is the AVIXA DISCAS rule for basic decision making. To make every pixel of detailed content visible, the picture height must be the vertical resolution times the distance divided by 3,438. Enter your screen, text size and distance below.
The values shown are an example. Replace them with your own.
How it is calculated
- Picture height of a 16:9 screen = 0.4903 × diagonal; width = 0.8716 × diagonal.
- Smallest readable character for basic reading = viewing distance ÷ 200 (AVIXA DISCAS, basic decision making, acuity factor 200).
- Farthest distance = 200 × (your smallest letter in pixel rows ÷ vertical resolution × picture height).
- Smallest screen = the picture height at which your smallest letter reaches distance ÷ 200, converted to a diagonal.
- Picture height for full detail = vertical resolution × distance ÷ 3,438, which is one arc minute per pixel.
What the standard says
ANSI/INFOCOMM V202.01:2016, Display Image Size for 2D Content, known as DISCAS, defines two kinds of viewing. Basic decision making covers content such as signage, with an acuity factor of 200. Analytical decision making covers detailed content, with an acuity factor of 3,438. AVIXA's online calculator gives the minimum element height for the basic case as a share of the picture height, for example 1.5% when the farthest viewer sits two to three picture heights away, and 5% at nine to ten picture heights. The full standard is paid, so the analytical formula here comes from a trade article that quotes it; check the current edition, as AVIXA's calculator refers to a 2026 revision.
A common sign-industry rule of thumb is one inch of letter height per ten feet of distance, which is about distance ÷ 120. It is not a standard. It asks for larger text than the DISCAS minimum, so use it when you want comfortable reading rather than the least that works.
Dense dashboards and spreadsheets are an analytical case, and they need either a large screen close by or a few big numbers instead. Check the hardware guide for players and read about screen orientation, resolution and aspect ratio.
What size screen do I need for a given viewing distance?
Choose your smallest text, then use the second block above. With 40 pixel rows of capital height on a 1080p screen, a viewer at 6 metres needs a picture about 81 cm high, which is a screen of roughly 65 inch diagonal.
How far can people read a 55 inch screen?
It depends on how small your text is. Enter your smallest capital letter in pixel rows: the farthest viewer is shown at the top. The minimum for basic reading is distance ÷ 200.
Is 1 inch of text per 10 feet a standard?
No. It is a rule of thumb from sign makers, about distance ÷ 120. The AVIXA DISCAS minimum for basic reading is distance ÷ 200.
Sources: AVIXA: DISCAS display image size for 2D content · AVIXA: DISCAS analytical decision making calculator · Commercial Integrator: how to size a digital display