Question 1

How much sun do I need for vitamin D?

Accepted Answer

Most people need 10-30 minutes of midday sun exposure on face and arms, 2-3 times per week to maintain adequate vitamin D levels. People with darker skin need longer exposure. The exact time depends on your skin type, latitude, season, and UV index.

Question 2

What is the Fitzpatrick skin type scale?

Accepted Answer

The Fitzpatrick scale classifies skin into 6 types based on how it responds to UV exposure. Type I (very fair, always burns) to Type VI (dark brown/black, never burns). Your skin type determines how quickly you burn and how much vitamin D you produce.

Question 3

Can I get vitamin D through glass?

Accepted Answer

No. UVB rays that produce vitamin D are blocked by most window glass. You need direct skin exposure to sunlight (or a supplement). Sunscreen with SPF 30+ also blocks about 97% of UVB, significantly reducing vitamin D production.

Question 4

Should I use sunscreen?

Accepted Answer

For brief vitamin D exposure (under the safe time for your skin type), sunscreen is not necessary. For longer exposure, always apply SPF 30+ sunscreen. The small amount of vitamin D exposure needed is well under the time it takes to burn.

Sun Exposure
Safe Time & Vitamin D

Sun Exposure & Vitamin D

How the Calculator Works

UV Index Guide

Fitzpatrick Skin Types

Tips & Limitations

Medical Disclaimer

Frequently Asked Questions