Vitamin D Sun Exposure Calculator
Estimate vitamin D synthesis from sun exposure.
Enter your values
ⓘ Live results
Results
- Estimated vitamin D generated
- 3,675 IU
- Note
- Rough midday summer sun estimate
Quick answer
Vitamin D synthesis from sunlight depends on skin area exposed, sun intensity, exposure time and skin pigmentation.
IU (rough estimate) = base rate x exposed body fraction x minutes x skin factor
How to use the Vitamin D Sun Exposure Calculator
- 1Enter approximate exposure time, percent of skin exposed and skin tone.
- 2This is a rough population-level estimate — actual synthesis varies hugely with latitude, season, time of day, cloud cover and sunscreen use.
- 3Balance sun exposure with skin cancer risk; consult a doctor about vitamin D testing and supplementation rather than relying on sun exposure alone.
Worked example
Using the values the calculator loads with:
Inputs
- Exposure time15 minutes
- Body surface exposed25 %
- Skin toneMedium
Results
- Estimated vitamin D generated3,675 IU
- NoteRough midday summer sun estimate
Frequently asked questions
Does sunscreen block vitamin D synthesis?
Yes, properly applied sunscreen significantly reduces UVB-driven vitamin D production.
Is sun exposure a reliable vitamin D source?
It's variable and risky for skin health; many people rely on diet and supplements, especially in winter.
About this calculator
- Built and reviewed by James Whitfield · How we build and test calculators
- Report an error
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.