About SunStoke

Most sun advice comes down to two words — “wear sunscreen” — and then leaves out everything that actually matters: how much to use, how often to put it back on, what the day’s UV index means, and what clothing and shade do that a bottle cannot. SunStoke exists to fill in those specifics with small, honest tools and plain-language guides, so you can enjoy the sun without quietly paying for it later.

Rather than long articles you have to read end to end, the site is built around a handful of single-purpose calculators, each aimed at one decision. The SPF Reapplication Timertells you the latest time to put more sunscreen on, on the FDA’s rule. The UV Index Category Checker puts the day’s forecast in its WHO category with what WHO and the EPA say to do. The Sunscreen Amount Calculator turns the 2 mg/cm² density SPF is tested at into grams and ounces for the parts of you that are exposed, never below the FDA’s one ounce for a whole body. The Sunburn Risk Category adds what WHO says water, sand, snow and altitude add. And Vitamin D and the Sun quotes the NIH on vitamin D without prescribing any sun. Since October 2026 no tool here gives a time in the sun or a tanning time: WHO advises against burn times, and there is no safe tan.

Beyond the calculators, the blog and learn section cover how SPF really works, chemical versus mineral filters, how much to apply, reading the UV index, the myths around tanning, protecting different skin types, and what a sunburn is; and the Sun & Skin Museum is a browsable collection on the sun itself, the biology of human skin, the history of sunscreen and cosmetics, and ultraviolet light, with every entry, image, and fact drawn from Wikipedia and Wikimedia Commons.

A few things worth stating plainly. SunStoke is an independent site, not a clinic, and not affiliated with any sunscreen brand or manufacturer. It is supported by advertising, which is how the tools stay free with no account required. Everything here — every amount, category, and article — is general educational information built on published conventions and the numbers you enter, not personalised medical or dermatological advice. Skin, medication, and UV conditions vary enormously from person to person and day to day, so for anything concerning a mole, a burn, a reaction, or a skin condition, see a doctor or a dermatologist. If a tool looks off, or there’s a calculator you wish existed, the contact page is the place to say so.