D-Fine
Track sun, food, vitamin D
Free · Designed for iPhone. Not verified for macOS.
Know exactly how much vitamin D you get from sunlight, food, and supplements — calculated for your skin, your location, and the time of day. One clear number, every day.
Know exactly how much vitamin D you're getting. Every day.
D-Fine tracks your vitamin D from three sources — sunlight, food, and supplements — and tells you if it's enough, based on your skin, your location, and the time of day.
THE PROBLEM
Vitamin D deficiency is one of the most common in the world, even among people who spend time outdoors. The issue isn't laziness. It's that no one can tell how much sun they actually need. It depends on where you live, the time of day, your skin type, what you're wearing. You can't figure that out by feel.
THREE SOURCES, ONE NUMBER
Until now, there was no way to see all the sources of vitamin D together. D-Fine combines sunlight, food, and supplements into a single daily figure — your IU today versus your personalized daily target. If you're taking a supplement, you'll finally know whether it's the right dose for you, today, in this season.
WHAT D-FINE DOES
Sunlight — D-Fine reads your time in daylight from your iPhone and Apple Watch, then calculates the IU your skin actually synthesized, factoring in UV index, sun angle, cloud cover, your Fitzpatrick skin type, how much skin is exposed, and any SPF you logged.
Food — Log meals containing vitamin D. D-Fine adds the IU to your daily total.
Supplements — Track your daily supplement dose. D-Fine warns you before you cross safe thresholds.
WHO IT'S FOR
People who live far from the equator, work indoors, have darker skin, are over 50, or just want to stop guessing.
PRIVACY
All processing happens on your device. Your profile syncs through your private iCloud container — only you can read it. Anonymous usage data is strictly opt-in (default OFF), uses a non-persistent install ID, and contains no Apple identifiers or personal information.
APPLE WATCH
With an Apple Watch, D-Fine measures your Time in Daylight continuously and passively, the way Apple intended. Without it, the app falls back to estimating from outdoor workouts and UV conditions — still useful, just less precise.
D-Fine is not a medical device. It's a science-based calculation tool to help you understand your vitamin D intake. For medical concerns, talk to your doctor.
Privacy Policy: https://d-fine.app/privacy
Support: https://d-fine.app/support
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, Airbag Studio Srl, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Health & Fitness
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Location
- Identifiers
- Usage Data
- Sensitive Info
- Diagnostics
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Airbag Studio Srl
- Size
- 13.4 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 17.4 or later.
- iPhone
Requires iOS 17.4 or later. - Mac
Requires macOS 14.4 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.1 or later. - Apple Watch
Requires watchOS 10.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Airbag Studio Srl