Shade asks for your Fitzpatrick skin type, from I to VI, because the same UV index means very different burn times for different skin. Your skin type sets the typical dose at which your skin starts to redden, and your estimated burn time is built on it.
The six skin types
- Type I: very fair, always burns, rarely tans.
- Type II: fair, burns easily, tans slowly.
- Type III: medium, sometimes burns, tans gradually.
- Type IV: olive, rarely burns, tans easily.
- Type V: brown, very rarely burns.
- Type VI: dark brown to black, rarely burns.
You pick your type once and can change it later if your first guess doesn’t match how your skin behaves.
How skin type changes the estimate
Each type has a standard minimal erythemal dose: the amount of UV that typically causes a just-visible redness. Type I reaches it much sooner than type IV. Shade takes that dose for your type, divides it by the UV you’re under and keeps a margin below it.
You also choose your protection: bare skin, sunscreen or covered up. Sunscreen is counted conservatively, well below the SPF on the bottle, because most people apply less than the tested amount.
When you’re not sure
Skin type is a self-assessment, so it’s an approximation. If you’re unsure between two types, pick the fairer one. You can also compare the result with how your skin has actually reacted in the past. If you have very fair skin, the fair skin page explains how Shade fits in.
Where the numbers come from
UV data comes from Apple Weather. Skin-type doses follow standard Fitzpatrick values, and UV guidance follows the WHO UV Index. Medication, recent sun and individual skin all shift the real answer, so treat the result as an estimate.
Frequently asked questions
What is the Fitzpatrick skin type?
It’s a six-point scale dermatologists use to describe how skin reacts to sun, from type I, which always burns and rarely tans, to type VI, which rarely burns. Shade uses it to pick a typical burning dose for your skin.
How do I know which skin type I am?
Shade describes each type in plain words, based on how your skin usually reacts after time in strong sun without protection. If you’re between two types, choosing the fairer one gives a shorter, more cautious estimate.
Do darker skin types never burn?
They can still burn, just after a larger dose. Shade gives every skin type a burn-time estimate, and the WHO advice on high UV applies to everyone.