The rule: every 20 minutes, look at something about 20 feet (six metres) away for 20 seconds. It lets the focusing muscle inside your eye relax after holding near focus. What it treats, and what it does not, is in the 20-20-20 rule explained. This page is only about making it happen.
macOS has no built-in reminder for it. Screen Time limits apps; it does not prompt breaks. Calendar and Reminders are built for appointments, not for a 20-minute cycle that runs all day. So you need one of the four options below.
What a good reminder needs
- It comes from outside your head. Deciding to remember does not survive an afternoon of focused work.
- It is short and easy to dismiss. A prompt that costs more than the break gets switched off.
- It knows when to stay quiet. A reminder during a call or a screen share gets uninstalled the same day.
The four options
| Option | Best for |
|---|---|
| Terminal one-linerFree; nothing to install | Trying the habit for a day |
| StretchlyFree, open source | Full breaks you can configure |
| Time OutFree, with optional paid extras | Micro and long breaks, Mac-native |
| Skopia$4.99 one-time | 20-20-20 plus blink prompts, quiet on calls |
1. A Terminal one-liner
Open Terminal and paste this line. It sends a notification every 20 minutes (1200 seconds) until you close the window or press ⌃C.
while true; do sleep 1200; osascript -e 'display notification "Look at something 6 metres away for 20 seconds" with title "20-20-20"'; done
If no notification appears, open System Settings → Notifications and allow notifications for Script Editor, which is the app macOS shows them under.
It is free and takes ten seconds. It also stops when you close Terminal, does not pause on calls, does not time the 20 seconds, and fires while you present. Use it to find out whether you want the habit, then pick a real tool.
2. Stretchly
A free, open-source break timer for Mac, Windows and Linux. It has two kinds of break: short mini breaks and longer breaks. Both intervals and durations are configurable, so you can set mini breaks to every 20 minutes for 20 seconds. Breaks appear as a window over your work, which you can postpone or skip. It can also count time away from the computer as a break.
Choose it if you want full control and do not mind a break window. It is a break timer, so it does nothing between breaks.
3. Time Out
A long-standing Mac break app with two break types: frequent micro breaks and less frequent normal breaks. Set the micro break to 20 seconds every 20 minutes and you have a 20-20-20 timer. The core app is free; extra features are paid. Breaks dim the screen by default, which is effective and also hard to ignore.
Choose it if you want a Mac-native app with many options and you also want longer stretch breaks.
4. Skopia
Skopia is our app, so weigh this paragraph accordingly. It is a menu bar app built around a different problem: blink rate, which falls by roughly two thirds during focused screen work. Its main job is a small prompt to blink fully, every 20 seconds by default. The 20-20-20 timer is built in and on by default: every 20 minutes, a 20-second prompt to look into the distance. A separate palming break runs every 60 minutes.
Two details matter for the 20-20-20 part:
- It stays quiet when it should. On a call, while recording the screen, in full screen, or in an app you mark as deep focus, all timers freeze and resume where they stopped.
- Timers do not stack. During a rest window the other countdowns hold, so you never get two prompts at once.
The 20-minute interval and 20-second length are fixed. If you want longer breaks, Stretchly and Time Out let you set them, and you can run either one alongside Skopia.
Which one to choose
- Only want to try the rule: the Terminal line.
- Want long breaks and stretching too: Stretchly or Time Out.
- Your eyes burn or feel gritty, not just tired: a break timer alone will not fix that, because dry eye comes from blinking, not focusing. Use a blink prompt. The options are compared in blink reminder apps for Mac.
- You spend much of the day on calls or presenting: pick a tool that pauses automatically, or you will switch it off within a week.
Making the break count
- Make the distance real. A wall two metres away keeps your focusing muscle working. Use a window or the far end of the room, and use the same target every time.
- Take longer when you can. The one study that tested 20-second breaks found them too short to change symptoms, and suggested one to two minutes. Treat 20 seconds as the minimum.
- Blink during the break. A few slow, full blinks while you look away rebuild the tear film.
- Do not chase every break. Twelve in a working day is a good day.
Johnson, S. & Rosenfield, M. (2023). 20-20-20 Rule: Are These Numbers Justified? Optometry and Vision Science, 100(1), 52–56.
20-20-20 and blinking, in one quiet app.
Skopia runs the 20-20-20 timer and a blink prompt together, and holds both while you are on a call or sharing your screen. One-time purchase. No camera, no subscription, no account.
Get Skopia — $4.99 →