Vitamin D Sun Exposure Calculator
Latitude + season + skin = mins needed
📚 Learn more — how it works, FAQ & guide Click to expand
Learn more — how it works, FAQ & guide
Click to expand
Vitamin D Sun Exposure Calculator
How many minutes in the sun for vitamin D synthesis without burning? Latitude + season + skin type + uncovered area give the answer. Most northern-hemisphere residents need supplements October-March.
How to use this tool
- 1
Latitude + month
UVB intensity varies dramatically.
- 2
Skin + body coverage
Type I (very pale) → VI (very dark).
- 3
See minutes
For ~1000 IU vitamin D synthesis.
Frequently Asked Questions
Why latitude matters?
Above 35° latitude, October-March, sun is too low for UVB to reach skin in usable doses. Berlin/London/NYC residents need supplements 5+ months/year, regardless of sunny weather.
Sunscreen blocks vitamin D?
SPF 15+ blocks 95%+ of UVB. So either: 5-10 min sun before sunscreen, then apply for rest of exposure. Or supplement.
Is more sun better?
No. After ~20 min in summer mid-day, vitamin D synthesis plateaus while skin damage continues. The risk-benefit curve flips.
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100% Privacy. This tool runs entirely in your browser. Your data is never uploaded to any server.