Personal Sun Need Calculator

An evidence-grounded estimate of how much sun, supplementation or strategic holiday-sun your body actually needs. Built on a 125 nmol/L (50 ng/mL) higher-end sufficiency target, honest about the UK winter, and direct about where most UK adults sit.

Step 1 of 2: your profile

1. Skin type (Fitzpatrick)

Pick the closest fit. This is the single biggest driver of how long your skin needs in the sun.

2. Age band

Cutaneous synthesis declines roughly fifty per cent between age twenty and seventy, and keeps falling.

3. UK region

Latitude matters. Scotland sits five degrees north of Southern England; less UVB reaches the skin.

4. Dress and coverage

How much skin is typically exposed during outdoor time in summer.

5. Current supplementation

If you're already taking vitamin D, the engine factors it in.

6. Pregnancy or breastfeeding

Vitamin D guidance differs in pregnancy. We render a pregnancy-specific summary if relevant.

7. Season you'd like the answer for

Sun synthesis in the UK is effectively zero between late September and late March. If you pick winter, we say so honestly.

8. Ethnic origin (optional)

Optional. If provided, this refines the starting estimate of where your 25-hydroxyvitamin D level sits in the UK. Skip if you'd rather not say.

Your next step

You have the picture. Here is what to do with it.

Keep going, free Sun Spectrum Explainer Understand the light your body actually responds to. Open Sun Spectrum Explainer →
Work with Omar, 1-2-1 Turn this into your plan In a 1-2-1, Omar maps your results to a plan that fits you and removes the biggest drivers first. Because everyone is different. Work With Omar