Sunburn Time Calculator — How Long Before You Burn by UV Index

A sunburn time calculator tells you how many minutes of unprotected sun exposure it takes to start burning, based on today's UV Index and your skin type.

UV Index to burn time — approximate reference (unprotected skin):

Times are estimates for unprotected skin. Altitude (UV increases ~10-15% per 1,000 ft), reflected surfaces (snow, water, sand), and cloud cover all shift these numbers.

What the UV Index doesn't tell you:

The UV Index peaks around solar noon — typically 11am to 2pm. A UV 5 day isn't dangerous at 7am. It's dangerous at 1pm when the index is actually at its rated level. UV accumulates throughout the day, so total exposure time matters, not just the peak reading.

How SPF extends your window:

SPF 30 theoretically lets you stay out 30x longer than unprotected. If you'd burn in 20 minutes unprotected at UV 8, SPF 30 extends that to about 10 hours — but only if you apply enough (1 oz for full body) and reapply every 2 hours. Sweat and swimming defeat most SPF 30 products within an hour without reapplication. Learn more in Best Weather App for Runners — Heat Index, Wind Chill, and Storm Timing. Learn more in Best Weather App for Hiking in 2026.

For UV Index 6 and above, keeping Neutrogena Ultra Sheer Dry-Touch Sunscreen SPF 100 in your bag is the simplest protection. It's lightweight enough that the "I forgot it" excuse doesn't hold up.

Calculate your exact burn time by skin type and UV Index →