Tanning Time Calculator
How long can you stay in the sun before you burn? Pick your skin type, set the UV index and your SPF, and get a personal estimate based on the WHO erythemal UV model.
Don’t know it? Check the live UV index for your location →
Burn time by skin type (no sunscreen)
Approximate minutes until unprotected skin reddens, at three common UV levels. These come straight from the calculator’s model.
| Skin type | UV 3 | UV 6 | UV 9 |
|---|
How to use it
- Pick your skin type. The Fitzpatrick scale runs I (very fair) to VI (deep brown). Take the skin type quiz if you’re unsure.
- Set the UV index. Use the live UV index for where you are, or your weather app’s figure.
- Add your SPF. Sunscreen multiplies your safe time — but only if you apply enough and reapply.
- Read your safe time. Treat it as a ceiling, not a target. Come out before then to build a tan with less risk.
Why “safe time” is a maximum, not a goal
The figure above is roughly when unprotected skin would start to redden (one Minimal Erythemal Dose). Skin damage begins well before visible burning, so the safest approach is short, repeated sessions at lower UV — see how to tan safely without burning. Pair this with the SPF Calculator to time reapplication.
Frequently asked questions
How long can I stay in the sun before I burn?
It depends on your skin type and the UV index. As a guide, fair Type II skin burns in about 17 minutes at UV index 8 with no sunscreen; olive Type IV skin lasts around 37 minutes in the same conditions. Enter your details above for a personal estimate.
How does the calculator work?
It uses the WHO/WMO erythemal model. Erythemal UV power equals the UV index × 0.025 W/m². Your skin’s Minimal Erythemal Dose (the energy needed to redden it) divided by that power gives the time to burn. SPF multiplies that time.
Does SPF really multiply my safe time?
In theory yes — SPF 30 lets through about 1/30th of the UV, so it roughly multiplies burn time by 30. In practice most people apply far too little and miss spots, so treat the SPF figure as a best case and reapply every two hours.
Is any amount of tanning “safe”?
A tan is your skin’s response to UV damage, so there is no completely risk-free tan. This tool helps you avoid burning, which carries the highest skin-cancer risk. Lower UV, shorter sessions and good SPF reduce the harm.
Your tan, planned by the hour.
Everything on this site, plus live UV by the hour, a burn-timer that counts down for your skin, SPF reapply reminders and push alerts the moment your safe window opens.