Sunbathing Calculator
Calculate safe sunbathing time and required SPF based on UV conditions and your skin type
Sun Safety Calculator
Higher altitude increases UV exposure (~4% per 300m)
Water and snow reflect UV rays, increasing exposure by ~25%
Medium skin, tans easily after initial burn
Use 1 for no sunscreen protection
Sun Safety Results
Calculation Details
Base burn time: 30 minutes (Skin Type 3)
UV Index: 5 (Moderate)
Altitude factor: 1.00x
Reflection factor: 1.00x (normal)
SPF protection: 30x
Safety Recommendations
• Reapply sunscreen every 2 hours
• Wear protective clothing and sunglasses
• Stay hydrated and seek shade when possible
Example Calculation
Beach Day Example
Conditions: Sunny summer day at beach
UV Index: 8 (Very High)
Altitude: Sea level (0m)
Environment: Water (reflection factor: 1.25x)
Person: Fair skin (Type II), SPF 30
Calculation
Base burn time: 20 minutes (Type II skin)
Safe time = (20 × 30) ÷ (8 × 1.0 × 1.25)
Safe time = 600 ÷ 10 = 60 minutes
Result: 1 hour safe sunbathing time
Fitzpatrick Skin Types
UV Index Scale
Sun Safety Tips
Apply sunscreen 20 minutes before sun exposure
Reapply every 2 hours or after swimming/sweating
Wear UV-blocking sunglasses and protective clothing
Seek shade between 10 AM and 4 PM when UV is strongest
Stay hydrated with plenty of water
Understanding Sun Safety and SPF
How SPF Works
Sun Protection Factor (SPF) indicates how much longer you can stay in the sun without burning compared to wearing no sunscreen. SPF 30 means you can theoretically stay in the sun 30 times longer than without protection.
UV Radiation Types
- •UVA: Penetrates deep into skin, causes aging and wrinkles
- •UVB: Causes sunburns and most skin cancers
- •UVC: Blocked by atmosphere, not a concern
Calculation Formula
Safe Time = (Base Burn Time × SPF) ÷ (UV Index × Altitude Factor × Reflection Factor)
- Base Burn Time: Time to burn without protection (skin type dependent)
- UV Index: Strength of UV radiation (0-15+ scale)
- Altitude Factor: ~4% increase per 300m elevation
- Reflection Factor: Water/snow adds ~25% more exposure
Important: This calculator provides estimates. Individual factors like medications, previous sun exposure, and skin sensitivity can affect results. Always use caution and consult healthcare providers for specific advice.