Vitamin D

GET YOUR VITAMIN D,
NOT A BURN.

Sunlight is one of the best sources of vitamin D, but a few minutes too many becomes a burn. Sunly works out how long you need at the current UV and your skin type to hit your daily target, then tells you when to cover up.

Free to download for iPhone and Android.

Sunlight, measured

The right dose of daylight

Minutes to your target

Sunly estimates the exact minutes you need at the current UV to reach your daily vitamin D goal, based on your skin type.

A cue to cover up

Once you have had enough for the day, Sunly reminds you to seek shade, so a healthy dose does not become a burn.

Track it over time

See your daily and weekly vitamin D from the sun build up, and keep your time in daylight in Apple Health.

How it works

Make the most of midday

Set your daily target

Tell Sunly your goal and skin type. From there it knows roughly how much sun translates into vitamin D for you.

Go out when UVB is there

Vitamin D production needs UVB, which is strongest around midday. Sunly tells you when conditions are actually worth it.

Expose a bit of skin, briefly

Arms and legs for a short window often do the job. You usually need far less time than it takes to burn.

Cover up when Sunly says so

Past your target, more sun adds risk without much benefit. Sunly cues you to shade or sunscreen at the right moment.

Read more in how much sun you need for vitamin D, or check the live UV index tracker.

Frequently asked questions

How much sun do you need for vitamin D?

It varies a lot with the UV level, your skin type, and how much skin is exposed. On a moderate-UV day many people make a useful amount in a short midday window, while higher UV needs less and lower UV needs more. Sunly estimates the minutes for your situation instead of using a single fixed number.

Can you get vitamin D through a window?

Generally no. Standard glass blocks most of the UVB that triggers vitamin D production, so sitting behind a window does not count. You need direct outdoor sunlight, which is what Sunly tracks.

How does Sunly estimate vitamin D?

Vitamin D mode uses the current UV index and your skin type to estimate the minutes needed to reach your daily target, then reminds you when to seek shade. It is a guide to help you make the most of sunlight and is not medical advice.

Is sun the only way to get vitamin D?

No. Diet and supplements also contribute, and they matter most in winter or at higher latitudes when UVB is weak. Sunly focuses on the sunlight side, helping you use the daylight you do get without overdoing it.

Get Sunly

ENJOY THE SUN.
SKIP THE BURN.

Free to download. Set up your skin profile and get your first UV forecast in under a minute.

Coming soon to the App Store.

Now · Lisbon

UV 8

Very High

Reapply SPF

in 1h 45m

GET YOUR VITAMIN D,NOT A BURN.