Habits & desk health
20-20-20 eye break calculator
Enter how long you work at a screen and when you start to get a 20-20-20 break count and the times of your first breaks.
Each break means looking at something about 6 metres (20 feet) away for 20 seconds; you do not need to leave your desk.
How the break schedule is calculated
The 20-20-20 rule, promoted by the American Academy of Ophthalmology and the American Optometric Association, says: every 20 minutes, look at something about 20 feet (6 metres) away for 20 seconds. The calculator converts your screen time to minutes, divides by the interval and rounds down, so a break is only counted once a full interval has passed. Total break time is the number of breaks × 20 seconds, and each break time is the start time plus a whole number of intervals.
Worked example: 8 hours of screen work starting at 09:00 with the standard 20-minute interval. That is 480 ÷ 20 = 24 breaks, three per hour, at 09:20, 09:40, 10:00 and so on, with the last one at 17:00. All 24 together take 24 × 20 = 480 seconds, which is just 8 minutes spread across the whole day.
| Screen hours | Breaks every 20 min | Time on breaks | Breaks every 30 min |
|---|---|---|---|
| 2 h | 6 | 2 min | 4 |
| 4 h | 12 | 4 min | 8 |
| 6 h | 18 | 6 min | 12 |
| 8 h | 24 | 8 min | 16 |
| 10 h | 30 | 10 min | 20 |
| 12 h | 36 | 12 min | 24 |
Making eye breaks actually happen
Close work keeps the focusing muscles inside the eye contracted, and people tend to blink less while reading a screen, which dries the surface of the eye. A distant target lets focus relax, and it is a good moment for a few deliberate, full blinks. Looking at the wall behind the monitor is too close; a window, the far end of a room or a corridor works better.
The hardest part is remembering. Tie breaks to something that already repeats, such as sending a message, finishing a paragraph or a timer on your watch, and do not stack them into one long pause at lunch: the benefit comes from breaking up continuous focus. If you choose a 30- or 45-minute interval because 20 feels disruptive, that still beats none. Persistent blurred vision, headaches or eyes that stay dry and gritty after a rest day are reasons to have your eyes examined, because an uncorrected prescription or a poorly placed monitor is often the real cause. The rule eases discomfort; it does not change your eyesight.
Frequently asked questions
What is the 20-20-20 rule?
Every 20 minutes of screen use, look at something about 20 feet (6 metres) away for at least 20 seconds. It gives the eye's focusing muscles a short rest from close work.
How many 20-20-20 breaks do I need in an 8-hour day?
Eight hours is 480 minutes, so 480 ÷ 20 = 24 breaks. At 20 seconds each, they add up to only 8 minutes.
Does the 20-20-20 rule prevent eye damage?
It reduces symptoms of digital eye strain such as tired or dry eyes, but screens are not known to cause permanent damage. Ongoing problems should be checked by an optometrist.