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You're offline but you can still use all the features of the 20-20-20 Rule Timer! The timer, settings, notifications, and all other features work without an internet connection. Your preferences are saved locally on your device, so you can continue following the 20-20-20 rule and reducing eye strain even when you're not connected to the web.
Close the tab and open it again while offline, you can still reload the page and the timer will continue working as normal.
So if you want to concentrate without distractions like the internet, or if you're in a location with spotty connectivity, the 20-20-20 Rule Timer is still there to help you take care of your eyes!
Stats
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Streak
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When you are at the screen last 30 days
Which days you use it
Your stats will appear here
Use the timer and this fills in: a square for every day you use it, your streak, the hours you spend at the screen and the days you use it most. Nothing is recorded until you press start.
Your stats data are kept locally in your browser for four months, and never sent anywhere. You can export, import, delete stats data and turn stats off in Settings here.
What is the 20-20-20 Rule?
The 20-20-20 rule is a guideline created by American optometrist Dr. Jeffrey Anshel in 1991 to reduce digital eye strain (also known as computer vision syndrome).
The rule is simple: every 20 minutes of screen time, look at something at least 20 feet (6~ meters) away for at least 20 seconds. This gives your eye muscles a chance to relax and helps prevent the fatigue that builds up from prolonged screen use.
Dr. Anshel also recommended a complementary 3-B approach alongside the rule:
Blink
Screen use significantly reduces your blink rate, leading to dry, irritated eyes. Make a continuous conscious effort to blink more often throughout the day.
Breathe
Extended screen work encourages shallow breathing and tension. Taking slow, deep breaths during breaks helps relieve both physical and mental stress.
Break
Every 20 minutes, look at something ~20 feet away (6~ meters) for ~20 seconds to let your eye muscles fully relax.
You can do more to help your eyes and body while working, read more about better alternatives and improvements to the 20-20-20 rule.
The 20-20-20 Rule Timer
This free web timer helps you follow the 20-20-20 rule without having to think about it.
Start the timer and work for 20 minutes. When it goes off, look at something 20 feet away for 20 seconds, then press start again to begin the next cycle. You can customise the work and rest durations, alarm tone, notifications, and more in settings, your preferences are saved automatically and can be reset in settings if needed. You can switch tabs and the timer will still alert you.
How to use the buttons
All seven controls, and when to use them.
- Start: Begins the timer. Starts with the work phase; press again after a work session ends to begin the rest phase.
- Pause: Pauses the countdown. Press Start to resume.
- Reset: Stops the timer and restarts from the beginning of the work phase.
- Mute: Appears only when the alarm is sounding. Silences that alarm without affecting future alarms. To mute all sounds, go to settings.
- Skip to rest: Ends the work phase early and starts the rest phase.
- Skip to work: Ends the rest phase early and starts the work phase.
- Add +60 sec: Extends the current countdown by 60 seconds (customisable in settings).
Using the timer offline
Everything keeps working without a connection.
The timer works even when you're offline, and notifications will still alert you of breaks as long as the page is open. You don't even need internet access to load the page after your first visit, so you can use the timer anywhere, anytime!
What is eye strain?
Eye strain (clinically known as asthenopia) is the tired, sore, or uncomfortable feeling your eyes get after prolonged use, particularly during close-up tasks like reading or screen work.
It's rarely serious, but it can affect your focus, comfort, and productivity. When you focus on something close up, the small muscles inside your eye (ciliary muscles) contract to adjust your lens, while your eye-movement muscles keep both eyes aligned, a process called vergence. Hold that focus for hours without a break, and those muscles fatigue, like any other muscle held under sustained tension.
Common causes of eye strain
Seven things that bring it on.
- Prolonged screen use without regular breaks
- Reading or writing for long periods
- Poor, dim, or overly bright lighting
- Screen glare or high contrast environments
- Reduced blinking while concentrating
- An outdated glasses or contact prescription
- Poor posture causing you to lean closer to your screen
Common symptoms
What eye strain feels like.
- Tired, burning, or itchy eyes
- Blurred or double vision
- Headaches around the eyes or forehead
- Increased sensitivity to light
- Neck, shoulder, or back discomfort from straining posture
What is computer vision syndrome?
Eye strain caused specifically by screens.
Computer vision syndrome (CVS), also called digital eye strain, is eye strain caused specifically by prolonged screen use. On top of standard eye strain symptoms, CVS is compounded by reduced blinking, screen glare, and the poor posture that often develops during device use. As screens dominate both work and leisure, CVS has become one of the most common workplace complaints, but it's largely preventable.
How to reduce eye strain and computer vision syndrome
Seven changes, roughly in order of payoff.
- Follow the 20-20-20 rule Every 20 minutes, look at something 20 feet away for at least 20 seconds to relax your focusing muscles.
- Set up your screen correctly Keep your screen 20-28 inches (50-70 cm) away, with the top at or slightly below eye level. Use a matte filter or adjust your environment to reduce glare.
- Optimise your lighting Avoid harsh overhead lights or bright windows behind your screen. Use soft, indirect lighting and adjust screen brightness to match your surroundings.
- Blink more consciously Screen use can cut your blink rate by half. Remind yourself to blink regularly, and consider lubricating eye drops if dryness persists.
- Keep your prescription up to date An incorrect prescription forces your eyes to work harder. Consider glasses with anti-reflective or blue-light filter coatings for screen use.
- Improve your ergonomics and posture Sit upright with your screen at arm's length. Take short breaks to stand, stretch, and roll your shoulders. Here are some helpful YouTube videos on setting up your workstation:
- Manage overall screen time Alternate between screen and non-screen tasks where possible. For children especially, balance digital time with outdoor activities.
Criticisms of the 20-20-20 rule
While experts broadly agree that regular screen breaks and distant focusing are important for eye health, the specific numbers in the 20-20-20 rule have faced scrutiny.
The numbers themselves
Twenty seconds, and twenty feet.
Critics point out that 20 seconds may not be long enough for meaningful eye muscle recovery, particularly after hours of continuous screen use. The "20 feet" target is also impractical in small rooms or confined offices.
What the rule leaves out
Posture, movement, and sticking to it.
A bigger criticism is that the rule addresses only eye health, ignoring the posture, movement, and circulation issues that also develop during long work sessions. Many researchers argue that breaks involving standing, stretching, and movement are far more beneficial than simply shifting your gaze.
Finally, consistency is the real challenge, studies show that 20-20-20 reminders improve eye strain symptoms while in use, but the benefits tend to fade once reminders stop, highlighting that habit-building matters more than the rule itself.
Better alternatives and improvements to the 20-20-20 rule
The 20-20-20 rule is a useful starting point, but we can do better.
Combining eye breaks with physical movement, standing, stretching, rolling your shoulders, taking a short walk, all benefits your whole body, not just your eyes. Some research also suggests that longer breaks every 60 to 90 minutes, or flexible "self-paced" breaks, can outperform rigid schedules. The timer's settings let you customise work and rest durations to find what works for you.
Suggested break and rest schedules
Try one of our preset schedules by clicking "Try now," or use them as a starting point and adjust the durations in settings to fit your own routine.
Health, posture and eye strain
Check your posture, then look 20 feet away. Stand up, stretch, roll your shoulders and take a few deep breaths.
Work, productivity and concentration
Two minutes stretching and reflecting on what you've done, two moving around, then a minute to plan the next session.
Studying, revision and learning
Two minutes going back over what you studied, one to stretch and note your progress, three to walk around. Leave your phone alone.
Deep concentrated work
Stretch and reflect for two minutes, move around for two more, then plan your next block before you sit back down.
Eye care
Spend a minute on how your eyes feel, blinking to re-lubricate them. Use the second looking at things at different distances.
Mental wellbeing and health
A minute on your posture and looking into the distance. For the rest, close your eyes, breathe slowly and notice how your body feels.
These are suggested starting points, not rules. Adjust the durations in settings to match your own rhythm and needs.