20-20-20 Rule Calculator — Eye Strain & Screen Break Planner
The 20-20-20 rule is the most widely recommended guideline for reducing digital eye strain: every 20 minutes of screen time, look at something at least 20 feet (6 metres) away for 20 seconds. Enter your daily screen hours to find out how many breaks you need and how much total rest time that adds up to.
hours
minutes
seconds
Look 20 ft (6 m) away for 20 seconds each break
- 1
Convert screen hours to minutes
8 × 60 = 480 - 2
Breaks per day = ⌊screen minutes ÷ interval⌋
⌊480 ÷ 20⌋ = 24The floor (⌊ ⌋) discards any partial interval at the end of the day.
How does this calculator work?
Every 20 minutes of screen time, look at an object ≥ 20 feet away for 20 seconds. On an 8-hour screen day this means 24 breaks totalling just 8 minutes. The calculator shows your daily break count and total rest time for any screen schedule and break frequency.
Formula
How this is calculated
Extended screen use causes the ciliary muscles in the eye to stay contracted to focus on a close object, leading to fatigue, blurred vision, and headaches — a cluster of symptoms called computer vision syndrome (CVS) or digital eye strain. Looking at a distant object (≥ 20 ft / 6 m) relaxes those muscles.
The 20-20-20 rule quantifies a practical rest schedule: a 20-second break every 20 minutes of screen time. This calculator lets you adjust both the interval and the break duration. It divides your total daily screen time by the chosen interval to find the number of breaks, multiplies by the break length to find total rest time, and shows that as a percentage of your screen session. Following the classic 20-20-20 rule on an 8-hour screen day means 24 breaks totalling 8 minutes of eye rest — less than 2 % of the day.
The calculator follows the clinical recommendation as published by the American Academy of Ophthalmology. It covers only micro-breaks for focusing relief; it does not replace advice on viewing distance (arm's length), monitor brightness, or correction for screen use. People experiencing persistent eye strain, dryness, or changes in vision should consult an optometrist.
Frequently asked questions
Research supports that regular breaks reduce eye fatigue and focusing difficulty. The American Academy of Ophthalmology recommends it as a simple, no-cost way to ease computer vision syndrome symptoms. For severe dryness or pain, see an eye care professional.
Any object roughly 6 metres (20 feet) from your eyes, such as a window view, a wall at the far end of a room, or trees outside. The key is that the object is far enough that your eyes no longer need to accommodate (converge and focus) for close-up work.
Yes. Studies show people blink two to three times less often when focused on a screen, which contributes to dry eyes. Consciously blinking fully every few minutes is a complementary habit. Some eye doctors recommend artificial tears alongside the 20-20-20 rule.
TG we-Calculate Editorial Team. (2026). 20-20-20 Rule Calculator — Eye Strain & Screen Break Planner [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/2020-vision-calculator
TG we-Calculate Editorial Team. "20-20-20 Rule Calculator — Eye Strain & Screen Break Planner." TG we-Calculate. 2026. https://we-calculate.com/calculator/2020-vision-calculator.
TG we-Calculate Editorial Team, "20-20-20 Rule Calculator — Eye Strain & Screen Break Planner," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/2020-vision-calculator
@misc{wecalculate_2020_vision_calculator, title = {20-20-20 Rule Calculator — Eye Strain & Screen Break Planner}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/2020-vision-calculator}}, year = {2026}, note = {TG we-Calculate} }
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