About WhySkin

WhySkin is a small, independent site built around eight free skincare calculators and an ingredient checker — the kind of tools you reach for when you’re standing in front of the bathroom mirror or a crowded shelf trying to make one specific decision.

What each tool actually does

Every tool on WhySkin is built around a narrow, well-defined question, and we try to be upfront about the logic behind each one rather than presenting a black box:

• SPF Calculator (/spf-calculator/) takes your Fitzpatrick skin type and a chosen SPF and estimates how long that combination gives you before burning, plus roughly what share of UVB radiation the SPF value blocks. The Fitzpatrick scale and SPF-to-UVB-blocking relationship are both established, published dermatological reference points — the calculator is arithmetic layered on top of them, not a new claim about your skin.
• Skin Type Quiz (/skin-type-quiz/) asks about shine, tightness, and visible pore size at different times of day and maps your answers to one of the four commonly used skin type categories: oily, dry, normal, or combination.
• Skincare Routine Builder (/skincare-routine-builder/) takes your skin type and stated concerns and orders a standard AM and PM routine — cleanser, treatments, moisturizer, SPF — following the layering order that’s widely taught in skincare guidance: thinnest, most active products first, heavier occlusive products last.
• Skincare Ingredient Checker (/ingredient-checker/) cross-references the actives you list against a lookup table of ingredient pairs that are commonly flagged as conflicting (for example, certain acids and retinoids used at the same time) and tells you which combinations to watch, not whether a product is “good” or “bad.”
• Hair Type Guide (/hair-type-guide/) uses curl pattern and strand porosity to place your hair into one of the standard type/porosity groupings and lists the care characteristics generally associated with that group.
• Skincare Expiry Date Tracker (/expiry-date-tracker/) takes the date you opened a product and its printed Period-After-Opening (PAO) symbol — the little jar icon with a number of months on it — and does the date math to tell you when it’s past that window.
• Foundation Color Match Tool (/color-match-tool/) takes your undertone and depth and maps them to a shade family, along with named shades that typically fall in that range and ones to avoid. It narrows the field; it doesn’t replace testing a shade against your actual jawline in daylight.
• Beauty Budget Planner (/beauty-budget-planner/) is the one tool that isn’t about skin biology at all — you enter what you own and what it costs, and it adds up your true annual and monthly spend, ranked by cost per product, so you can see where the money in a routine actually goes.

None of these tools connect to a lab, a dermatologist’s office, or a product database. They run entirely in your browser: the numbers you enter are used to produce a result on the page and aren’t stored or sent anywhere by us.

Where the reference material comes from

The underlying logic — the Fitzpatrick scale, PAO symbols, ingredient interaction pairs, layering order, curl/porosity typing — comes from established, widely published dermatological and cosmetic-science conventions, not from anything we invented. If you want to go past the calculators and read about the ingredients and biology behind them, our Skincare Science section has separate galleries on active ingredients like retinol and niacinamide, plant-derived skincare extracts, and skin biology itself, with every entry, image, and fact sourced from Wikipedia and Wikimedia Commons and linked back to its source. We also publish articles on the blog and reference explainers under Learn that go deeper on specific ingredients and routine questions.

What this site is, and isn’t

WhySkin is independently run and supported by advertising on the site — that’s what keeps the tools free and keeps the lights on. We aren’t affiliated with any of the skincare brands, ingredient manufacturers, or dermatological bodies our content references.

Every result here is general information based on common conventions, not personalized medical or dermatological advice. Your skin, your product formulations, and your sun exposure vary in ways a calculator can’t see. If you have a persistent skin concern, a reaction to a product, or a question about a specific medical condition, talk to a board-certified dermatologist rather than relying on a result from this site.

Questions about a tool or something that looks off? See Contact.