Burn time chart: how long until you sunburn
Estimated minutes of unprotected sun exposure before skin starts to redden, by Fitzpatrick skin type and UV index. Find your row, check today's UV level, and treat the result as a ceiling — reflection off water, sand, or snow and higher altitude all shorten it.
| Skin type | UV 2 | UV 3 | UV 4 | UV 5 | UV 6 | UV 7 | UV 8 | UV 9 | UV 10 | UV 11 |
|---|---|---|---|---|---|---|---|---|---|---|
| I Very fair | ~1h 5m | ~44 min | ~33 min | ~27 min | ~22 min | ~19 min | ~17 min | ~15 min | ~13 min | ~12 min |
| II Fair | ~1h 25m | ~56 min | ~42 min | ~33 min | ~28 min | ~24 min | ~21 min | ~19 min | ~17 min | ~15 min |
| III Medium | ~1h 55m | ~1h 20m | ~58 min | ~47 min | ~39 min | ~33 min | ~29 min | ~26 min | ~23 min | ~21 min |
| IV Olive | ~2h 30m | ~1h 40m | ~1h 15m | ~1h | ~50 min | ~43 min | ~38 min | ~33 min | ~30 min | ~27 min |
| V Brown | ~3h 20m | ~2h 15m | ~1h 40m | ~1h 20m | ~1h 5m | ~57 min | ~50 min | ~44 min | ~40 min | ~36 min |
| VI Dark brown / black | ~5h 35m | ~3h 40m | ~2h 45m | ~2h 15m | ~1h 50m | ~1h 35m | ~1h 25m | ~1h 15m | ~1h 5m | ~1h |
How to read it
- These are first-redness estimates, not "safe" durations — DNA damage begins well before visible redness, and a tan is itself a damage response.
- Sunscreen multiplies the time: correctly applied SPF 30 turns 20 minutes into ~10 hours of theoretical protection — in practice, reapply every 2 hours because coverage degrades.
- Shorten your estimate by up to half near water, sand, or snow, and ~10% per 1,000 m of altitude.
- Photosensitizing medication (tretinoin, doxycycline, and others) can cut these times dramatically — see the guide.
The formula
UV index 1 equals 25 mW/m² of erythemally weighted irradiance, and each skin type has a typical minimal erythemal dose (MED). Minutes to burn = MED × 40 ÷ UV ÷ 60. Full details and MED values on the methodology page.