Sun Exposure Calculator (Sunburn Time)
Estimate how long skin can safely stay in the sun before burning, based on skin type and UV index, with or without sunscreen.
About the Sun Exposure Calculator (Sunburn Time)
How quickly unprotected skin burns in the sun depends heavily on two things: your skin's natural sensitivity (the Fitzpatrick skin type scale) and the day's UV index. This calculator combines both into a rough estimate of safe sun exposure time, with or without sunscreen.
Formula: Time to Burn (no protection) = Baseline Minutes at UV Index 3 × (3 ÷ UV Index). With sunscreen applied, that figure is multiplied by the SPF rating as a simplified protection factor.
Baseline burn times increase from Fitzpatrick Type I (very fair skin, burns fastest) through Type VI (deeply pigmented skin, burns slowest). This is an educational approximation, not medical guidance — actual burn time also depends on altitude, cloud cover, water or snow reflection, time of day and individual skin sensitivity, so always reapply sunscreen regularly regardless of what this calculator suggests.