Eye Strain Break Calculator
Apply the 20-20-20 rule to a screen session: how many eye breaks you should take, when they fall, and the total rest for your eyes.
How it works
Breaks = ⌊session minutes ÷ interval⌋ · Total eye rest = breaks × look-away seconds · 20-20-20: every 20 min, look 20 ft away for 20 sec
Staring at a near screen keeps your focusing muscles tensed and cuts your blink rate, which is what leaves eyes tired, dry and gritty. The 20-20-20 rule breaks that pattern: every 20 minutes, look at something at least 20 feet away for 20 seconds, letting the focusing muscles relax and prompting a few full blinks. This tool counts how many of those breaks fit your session and the total rest they add up to — a reminder that a handful of seconds, taken often, is what protects comfort over a long day.
Worked example
An 8-hour session is 480 minutes. At one break every 20 minutes that is ⌊480 ÷ 20⌋ = 24 breaks. At 20 seconds each, your eyes get 24 × 20 = 480 seconds, or 8 minutes, of distance-focus rest across the day.
Frequently asked questions
Why 20 feet specifically?
At roughly 20 feet and beyond, the eye's focusing muscle is essentially relaxed, so looking that far briefly releases the strain of constant near-focus. The exact distance is not magic — anything far away works; 20 feet is an easy target.
Does the 20-20-20 rule prevent long-term damage?
It mainly relieves digital eye strain — the transient fatigue, dryness and blur from screen use — rather than preventing conditions like nearsightedness. It is a comfort tool, and pairing it with good lighting and blinking helps most.
What else reduces screen eye strain?
Blink fully and often, position the screen a little below eye level and about an arm's length away, cut glare, and keep text large enough to read without leaning in. Regular breaks tie these habits together.
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Educational estimate only — not medical advice, diagnosis, or treatment. Individual needs vary; consult a qualified healthcare professional for decisions about sleep, hydration, nutrition, exercise, or ergonomics.