UV Exposure Time Calculator

Estimate how quickly sun exposure risk can increase based on UV index, skin type, sunscreen use, and retinoid use.

Use your local UV forecast if available.
Used for a simple sensitivity estimate.
A simple protective multiplier.
Retinoids can increase sun sensitivity.
How we calculate

We estimate exposure tolerance from a simple baseline by skin type, then adjust it using UV index, sunscreen use, and retinoid use.

  • Very fair: most sensitive
  • Medium: moderate sensitivity
  • Darker skin types: lower sensitivity in this simplified model
  • Sunscreen: increases estimated caution time
  • Retinoids: reduce estimated caution time