Personal Sun Need Calculator · Free

See how much sun your body actually needs, where you live.

A free, evidence-grounded estimate built from your skin type, age, dress and UK region. Honest about the British winter, and clear about where most of us actually sit.

Guess, or copy a one-size dose off a label Start from your skin, your latitude, your life
A few minutesNothing to measurePlain EnglishPharmacist-built
What this is for

A sun and vitamin D estimate made for you

Vitamin D from sunlight depends on your skin tone, your age, how much skin is uncovered, the season and how far north you live. This weighs all of that to estimate what your body needs, then tells you honestly when the UK sky cannot provide it. Everyone is different, so it is a starting point, not a verdict.

How it works

Three simple steps

1
Answer a few quick questions
Skin type, age, UK region, dress, the season you want the answer for, and a couple of optional details.
2
See your personal estimate
A clear read on how much sun you would need, and when the British winter means sunlight alone will not do it.
3
Know your next move
Plain guidance on sun, and where supplementation or a conversation with your pharmacist or GP fits, with no doses pushed at you.
What you walk away with

What you take away

  • A personal estimate of how much sun your body needs
  • An honest read on the UK winter, when the sky cannot help
  • Where supplementation or a pharmacist conversation fits for you
  • The remove-first idea in action: understand the gap before you reach for a bottle
Start the calculator

Everyone is different. This is an evidence-based estimate, not a diagnostic test.

Best for anyone unsure how much sun is enough, especially through the UK winter.

Created by justaskomar.co.uk. A free, evidence-based estimate, not a diagnostic test or a substitute for advice from your GP or pharmacist.

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