Health Calculators
Sunscreen reapplication timer.
Enter when you put sunscreen on, today’s UV index and what you are doing. Get the clock times to reapply and a live countdown. Based on Health Canada’s UV index guidance. Runs in your browser; nothing is sent or stored.
Your day
Reapply schedule
Fill the form and press Show reapply times.
How the schedule is worked out
The tool applies these published rules, in this order:
- Indoors: no schedule. The guidance covers time outdoors.
- UV 0 to 2 (Low): minimal risk, so no schedule, unless you tick bright snow and will be out for more than one hour. Health Canada then advises covering up and using sunscreen.
- UV 3 or higher: sun protection is recommended. You get a reapply time every 2 hours after you applied, until your time outside ends.
- Swimming or sweating a lot: same 2 hour clock, plus a reminder to reapply right after you swim or sweat a lot. Press “I just reapplied” when you do, and the clock restarts from that moment.
Worked example. Applied at 10:00 AM, UV 6 (High), outdoors for 6 hours (until 4:00 PM). Reapply at 12:00 PM and 2:00 PM. A 4:00 PM time is the end of your outing, so it is not listed.
No SPF × minutes. You will not see a “burn time” here. Multiplying SPF by minutes is not part of the guidance, and the 2 hour interval does not stretch with a higher SPF. Health Canada advises an SPF of at least 30 on uncovered skin.
UV index bands (Health Canada, WHO scale)
Sources (opened 2026-10-02): Health Canada, UV index and sun safety (bands, the UV 3 threshold, reapply every 2 hours and after swimming or sweating a lot, SPF 30 or more, bright snow); WHO, Global Solar UV Index: A Practical Guide (2002) (the international UV index scale). For general sun-safety advice see also the Canadian Cancer Society.
FAQ
Do I really need to reapply sunscreen every 2 hours?
Health Canada says to reapply sunscreen every 2 hours, or after you swim or sweat a lot, when the UV index is 8 or more, and its sun-safety advice also says to put on plenty of sunscreen and reapply every 2 hours. This timer uses that 2 hour interval.
At what UV index do I need sunscreen?
Health Canada says sun risk in Canada is highest when the UV index is 3 or higher, and advises sunscreen on skin you cannot cover at UV 3 to 7. At UV 0 to 2 the risk is minimal, except on bright, snowy days, when it advises covering up and using sunscreen if you are outside for more than one hour.
Does a higher SPF mean I can wait longer to reapply?
This tool does not multiply SPF by minutes, because that is not part of the published guidance. Health Canada advises an SPF of at least 30 on uncovered skin, and the reapplication interval stays 2 hours.
Do I need to reapply after swimming or sweating?
Yes. Health Canada says to reapply after you swim or sweat a lot, even if 2 hours have not passed. Use the “I just reapplied” button to restart the clock from that moment.
Do I need sunscreen on a cloudy day?
Health Canada says that in cool or slightly cloudy weather you still need to protect yourself, because UV still gets through. Use the UV index, not the temperature or cloud cover, to decide.
Does this timer work indoors?
It does not give a schedule for indoor time. The Health Canada guidance it relies on covers time outdoors, so choosing indoors shows no reapply times.
Staying out longer? Check the water intake calculator.
Disclaimer
General sun-safety information, not medical advice. Sunscreen is only one part of sun protection; shade, clothing, a hat and sunglasses matter too. People with skin conditions, a history of skin cancer, or on photosensitising medicines should follow their clinician’s advice. Check the label of your product for its own directions.