⏱️ Sunburn Time & SPF Reapplication Calculator
Estimate how fast you could burn in the current UV index for your skin type, and get an easy SPF reapplication timer for safer time outside.
Last Updated: November 2025 • Based on simplified UV‑index guidance and typical SPF behavior
Your Sun Exposure Estimate
-- min
approx. time to first burn (no protection)
-- min
approx. time to burn with SPF
2 h
recommended SPF reapply interval
--
next reapply times (if start set)
How these sunburn times are estimated
This calculator uses a simple model:
- Each skin type gets a baseline burn time at UV index 10 (for example, very fair ~10 minutes, fair ~15, medium ~20, olive ~25, dark ~30).
- We adjust for today’s UV index (higher UV = faster burn) and for reflective environments like water, beach, or snow (which effectively increase UV).
- SPF is treated as extending time‑to‑burn up to a point, but we cap the protection and still default to a 2‑hour reapply rule (or sooner with sweating/swimming).
Real‑world burn time varies with clouds, altitude, exact SPF application, and your individual skin. This is an educational estimate, not a guarantee of safety—if your skin looks or feels red, get out of the sun immediately.
Why Sunburn Time Matters
Even a few bad sunburns—especially in childhood and adolescence—can significantly increase your risk of skin cancer later in life. Knowing roughly how quickly you might burn in today’s conditions helps you plan shade breaks, clothing, and SPF reapplication instead of guessing.
Basic Sun Safety Rules
- Seek shade between 10am and 4pm when UV is strongest.
- Use broad‑spectrum SPF 30+ on all exposed skin and reapply at least every 2 hours.
- Reapply after swimming, towel‑drying, or heavy sweating—no matter what the label says.
- Wear hats, UV‑blocking sunglasses, and protective clothing whenever possible.