How much sun do I need for vitamin D?

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.

What is the Fitzpatrick skin type scale?

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.

Can I get vitamin D through glass?

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.

Should I use sunscreen?

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 & Vitamin D

How long is safe outside today, and roughly how much vitamin D will you make? Based on Fitzpatrick skin type and UV index.

Calculator

How the Calculator Works

Enter your Fitzpatrick skin type, current UV index, and approximate percentage of body surface exposed. The calculator estimates safe exposure time (below sunburn threshold), approximate vitamin D production, and burn risk time.

UV Index Guide

UV 1-2: Low (safe for most). UV 3-5: Moderate (protection recommended for extended exposure). UV 6-7: High (protection essential). UV 8-10: Very high (avoid midday sun). UV 11+: Extreme (limit all outdoor time).

Fitzpatrick Skin Types

TypeDescriptionBurn Response

IVery fair, freckles, red/blond hairAlways burns

IIFair skin, blue/green eyesBurns easily

IIIMedium skin, dark hairSometimes burns

IVOlive/light brown skinRarely burns

VBrown skinVery rarely burns

VIDark brown/black skinNever burns

Tips & Limitations

Check the UV index before planning sun exposure

Midday sun (10am-2pm) produces the most vitamin D but also the most UV damage

If your shadow is shorter than you, UV is high

Consider a vitamin D supplement in winter months at higher latitudes

Cover up or apply sunscreen after reaching your safe exposure time

Medical Disclaimer

This calculator provides estimates only. Actual vitamin D production and burn times vary significantly with cloud cover, altitude, reflection (snow/water), and individual factors. This tool does not replace dermatological advice. Protect your skin from excessive UV exposure.

Sun Exposure & Vitamin D

How the Calculator Works

UV Index Guide

Fitzpatrick Skin Types

Tips & Limitations

Medical Disclaimer

Frequently Asked Questions

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