UV Index & Skin Type Protection Reference

Unprotected and protected burn time, by UV index and skin type

UV index	Category	Skin type	Unprotected	SPF 15	SPF 30	SPF 50	Risk at 30 min, no sunscreen
2	Low	Type I Very fair; often red or blonde hair, freckles	66.7 min	1,000 min	2,000 min	3,333.3 min	45 · Moderate
2	Low	Type II Fair skin, light eyes	83.3 min	1,250 min	2,500 min	4,166.7 min	36 · Moderate
2	Low	Type III Medium; darkens after burning	100 min	1,500 min	3,000 min	5,000 min	30 · Moderate
2	Low	Type IV Olive or light-brown skin	150 min	2,250 min	4,500 min	7,500 min	20 · Low
2	Low	Type V Brown skin	200 min	3,000 min	6,000 min	10,000 min	15 · Low
2	Low	Type VI Deeply pigmented dark-brown to black skin	333.3 min	5,000 min	10,000 min	16,666.7 min	9 · Low
4	Moderate	Type I Very fair; often red or blonde hair, freckles	33.3 min	500 min	1,000 min	1,666.7 min	90 · Very High
4	Moderate	Type II Fair skin, light eyes	41.7 min	625 min	1,250 min	2,083.3 min	72 · High
4	Moderate	Type III Medium; darkens after burning	50 min	750 min	1,500 min	2,500 min	60 · High
4	Moderate	Type IV Olive or light-brown skin	75 min	1,125 min	2,250 min	3,750 min	40 · Moderate
4	Moderate	Type V Brown skin	100 min	1,500 min	3,000 min	5,000 min	30 · Moderate
4	Moderate	Type VI Deeply pigmented dark-brown to black skin	166.7 min	2,500 min	5,000 min	8,333.3 min	18 · Low
7	High	Type I Very fair; often red or blonde hair, freckles	19 min	285.7 min	571.4 min	952.4 min	100 · Extreme
7	High	Type II Fair skin, light eyes	23.8 min	357.1 min	714.3 min	1,190.5 min	100 · Extreme
7	High	Type III Medium; darkens after burning	28.6 min	428.6 min	857.1 min	1,428.6 min	100 · Extreme
7	High	Type IV Olive or light-brown skin	42.9 min	642.9 min	1,285.7 min	2,142.9 min	70 · High
7	High	Type V Brown skin	57.1 min	857.1 min	1,714.3 min	2,857.1 min	53 · High
7	High	Type VI Deeply pigmented dark-brown to black skin	95.2 min	1,428.6 min	2,857.1 min	4,761.9 min	32 · Moderate
9	Very High	Type I Very fair; often red or blonde hair, freckles	14.8 min	222.2 min	444.4 min	740.7 min	100 · Extreme
9	Very High	Type II Fair skin, light eyes	18.5 min	277.8 min	555.6 min	925.9 min	100 · Extreme
9	Very High	Type III Medium; darkens after burning	22.2 min	333.3 min	666.7 min	1,111.1 min	100 · Extreme
9	Very High	Type IV Olive or light-brown skin	33.3 min	500 min	1,000 min	1,666.7 min	90 · Very High
9	Very High	Type V Brown skin	44.4 min	666.7 min	1,333.3 min	2,222.2 min	68 · High
9	Very High	Type VI Deeply pigmented dark-brown to black skin	74.1 min	1,111.1 min	2,222.2 min	3,703.7 min	40 · Moderate
12	Extreme	Type I Very fair; often red or blonde hair, freckles	11.1 min	166.7 min	333.3 min	555.6 min	100 · Extreme
12	Extreme	Type II Fair skin, light eyes	13.9 min	208.3 min	416.7 min	694.4 min	100 · Extreme
12	Extreme	Type III Medium; darkens after burning	16.7 min	250 min	500 min	833.3 min	100 · Extreme
12	Extreme	Type IV Olive or light-brown skin	25 min	375 min	750 min	1,250 min	100 · Extreme
12	Extreme	Type V Brown skin	33.3 min	500 min	1,000 min	1,666.7 min	90 · Very High
12	Extreme	Type VI Deeply pigmented dark-brown to black skin	55.6 min	833.3 min	1,666.7 min	2,777.8 min	54 · High

Minutes are time to a just-perceptible burn (one minimal erythema dose), computed by the same uvExposure() and sunburnRisk()functions the calculators use. SPF figures assume the ideal, laboratory application density — real-world under-application and time between coats will shorten them.

How the table is derived

Five UV index values stand in for the five WHO exposure bands — Low, Moderate, High, Very High, and Extreme — and each is run through all six Fitzpatrick skin types. For every combination, the unprotected column and each SPF column call uvExposure() directly, which itself calls burnMinutes() from skin.ts: time to a burn is proportional to a skin type’s minimal erythema dose and inversely proportional to the UV index, then multiplied by SPF as an ideal factor. The risk column calls sunburnRisk() for a fixed 30-minute, unprotected, grass, sea-level exposure, so it isolates exactly how UV index and skin type change the outcome.

Two patterns fall out of the arithmetic rather than being asserted: reading down any UV index block, later (higher-numbered) skin types always tolerate at least as much unprotected time as earlier ones, because a higher minimal erythema dose is baked into the model for those types. Reading across skin types at increasing UV index, unprotected time only ever gets shorter, never longer — a higher UV index always costs you time, whatever your skin type. Neither pattern is hand-tuned; both are consequences of the same division that powers the calculators above, and the test suite for this page checks both hold for every row.

Frequently Asked Questions

Where do these numbers come from?

Every figure in this table is computed by calling the same uvExposure(), sunburnRisk(), and skin.ts functions that power the UV Index Safe-Exposure Calculator and the Sunburn Risk Score — nothing here is a separately hand-typed table, so it can't drift out of sync with the calculators.

Why do some 'protected minutes' figures look absurdly long?

This model treats SPF as an ideal, ceiling multiplier on the unprotected burn time — the same simplified assumption dermatology testing uses. At low UV or high SPF that arithmetic produces figures like 'over 40 hours,' which nobody actually gets in real life. It's a sign that the number on the bottle is a laboratory ceiling, not a real-world guarantee — see How SPF Actually Works for why reapplication and application amount matter more than chasing the arithmetic.

What does the 'risk score at 30 minutes' column assume?

It's the Sunburn Risk Score for a fixed, comparable benchmark — 30 minutes outside, no sunscreen, on grass, at sea level — so the only things changing across the column are UV index and skin type. Real conditions (sand, water, snow, altitude, and any SPF you're wearing) will move the number; use the Sunburn Risk Score tool directly to plug in your own day.

Is a skin type with a longer burn time 'safer' to leave unprotected?

It has more built-in headroom, not immunity. Every skin type in this table accumulates UV damage, and every skin type is safer with sunscreen, shade, and cover-up than without — see Protecting Your Skin by Type for what each type does and doesn't change about your risk.

This table is general information about a simplified sun-science model, not medical or dermatological advice, and not a personalised prediction for your own skin. Check the live UV forecast for your location, follow your sunscreen’s label, and see a physician or dermatologist about your own skin, moles, or sun sensitivity.

Use it with

UV Index Safe-Exposure Calculator— plug in today’s real UV index and your own skin type instead of the representative values in this table.
Sunburn Risk Score— add your own time outside, surface, altitude, and SPF for a score tailored to your day.
Understanding the UV Index— what the 0-to-11+ scale means and what raises it, in plain terms.