How Long in the Sun for Vitamin D? By Skin Type and Age

There is no single number: the time depends on how strong the sun is, your skin type, your age and how much skin is bare. These tables use the model behind the Sun Atlas map and the Sundi app.

Updated 2026-10-07. Education and wellness only, not medical advice.

How to read the tables

Full dose means about 1,000 IU of vitamin D from midday sun with about a quarter of the body bare (for example arms and legs) and no sunscreen on that skin. Time to burn is the time to reach one minimal erythemal dose, the start of sunburn, at that UV Index. The first number is a target and the second is a limit. Stop well before the limit, and in practice a safe session is well under the time to burn.

The Sundi app and this site assume that production falls by 1.25% for every year over 25 (down to 25% of the young-adult rate). That is why the age 65 column is almost twice the age 30 one.

UV Index 3: moderate (spring and autumn, or low sun)

Skin type	Typical skin	Full dose, age 30	Full dose, age 65	Time to burn
Type I	Very fair, always burns	12 min	22 min	44 min
Type II	Fair, burns easily	15 min	28 min	56 min
Type III	Light brown, sometimes burns	18 min	33 min	67 min
Type IV	Olive, burns a little	27 min	50 min	1.7 h
Type V	Brown, rarely burns	36 min	67 min	2.2 h
Type VI	Dark brown or black	59 min	1.9 h	3.7 h

UV Index 6: high (a typical summer noon in the Mediterranean)

Skin type	Typical skin	Full dose, age 30	Full dose, age 65	Time to burn
Type I	Very fair, always burns	6 min	11 min	22 min
Type II	Fair, burns easily	7 min	14 min	28 min
Type III	Light brown, sometimes burns	9 min	17 min	33 min
Type IV	Olive, burns a little	13 min	25 min	50 min
Type V	Brown, rarely burns	18 min	33 min	67 min
Type VI	Dark brown or black	30 min	56 min	1.9 h

UV Index 9: very high (the tropics and high summer)

Skin type	Typical skin	Full dose, age 30	Full dose, age 65	Time to burn
Type I	Very fair, always burns	4 min	7 min	15 min
Type II	Fair, burns easily	5 min	9 min	19 min
Type III	Light brown, sometimes burns	6 min	11 min	22 min
Type IV	Olive, burns a little	9 min	17 min	33 min
Type V	Brown, rarely burns	12 min	22 min	44 min
Type VI	Dark brown or black	20 min	37 min	74 min

What this means

Short and regular beats long and rare. Stop well before your skin goes pink.
More skin, less time. Arms and legs make far more than a face alone.
Darker skin needs longer, and pale skin burns sooner, so pale skin has the smallest margin between dose and burn.
Cover up after your dose. Use shade, a hat, sunglasses and SPF 30+ on skin that stays exposed.
Sun alone does not give too much vitamin D. Extra UV breaks the surplus down, but it keeps adding burn risk.

These are planning estimates for education and wellness. They are not medical advice. If you have a medical condition, take photosensitising medicine or have had skin cancer, talk to your doctor first.

Next: UV Index 2.5 explained · Sun safety on a vitamin D holiday · The Sun Atlas map

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