Comparison

MyCircadianApp vs Project Function

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

MyCircadianApp

This app tracks sunlight patterns, including sunrise, sunset, and UV index, to help you optimize your exposure. It features a vitamin D timer based on your skin type and environmental factors, and a lux meter to log light exposure. Additional tools include a compass and moon tracker.

Highlights
  • Hourly sunrise, solar noon, sunset tracking
  • Live UV index with hourly chart
  • Vitamin D timer with personalized recommendations
  • Lux meter for light tracking
  • Compass for sun directions
  • Moon tracker with phases
Features
Read full description

MyCircadian shows you what the sun is doing right now, where you are, and what to do with it. SUNLIGHT, HOUR BY HOUR • Sunrise, solar noon, sunset, daybreak and nightfall for your location • UVA and UVB windows, with the current sun angle • Live UV index with an hourly chart and today's peak VITAMIN D TIMER • Recommended time per side based on your skin type, the UV index, cloud cover and how much skin is exposed • Adjust for city, white sand, water or snow • Log every session and see the estimated IUs • See when vitamin D is available today, and how many days are left in the season LIGHT TRACKING • Lux meter that uses your phone's camera • Log light sessions and follow your daily light goal MORE TOOLS • Compass for sunrise and sunset directions • Moon tracker with phase, moonrise and moonset • UV index widget for your Home Screen • Multiple saved locations, imperial or metric units, adjustable text size MyCircadian is a wellness and education tool. It does not diagnose, treat or prevent any condition. Vitamin D figures are estimates. Talk to your doctor about sun exposure and supplements. Terms of Use: https://mycircadianapp.com/terms-of-use Privacy Policy: https://mycircadianapp.com/privacy-policy

About

Project Function

Features
Read full description

With the Project Function App, you can check in to our facility, manage your membership details, and book appointments. - Access digital membership pass - Book appointments and view session balance - Edit personal information and view membership details - Stay up-to-date with announcements from us! Download the app today! Features connectivity to Apple Watch (synced to HealthKit app)

Screenshots

MyCircadianApp4 screens
Project Function4 screens

Verdict

The call

The clearest difference is in-app purchases: Project Function at none against MyCircadianApp's 7. On price, update cadence, ads and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. MyCircadianApp sells 7 in-app purchases, starting at $3.99 per month. Project Function asks for nothing beyond the download.

UpkeepUpdate frequency

MyCircadianApp ships an update monthly, Project Function every 6 weeks. Both last shipped on November 12, 2026.

Scorecard1 real difference · 9 level
MyCircadianApp versus Project Function: the parameters behind the verdict, then further details
ParameterMyCircadianAppProject Function
PriceFreeFree
Rating4.9 (265 ratings) — better—
Positive reviews98.6% of reviews—
Number of ratings265 — better—
Update frequencyMonthly — betterEvery 6 weeks
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemium—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod, Apple Watch — better
Requires iOS15.1 — better15.5
Further details — not scored
Size66 MB222 MB
Age rating12+4+
DeveloperSarah Kleiner WellnessProject Function LLC

Bugs and requests

MyCircadianApp

Reported bugs

2 issues
  • Login screen freezes
  • Incompatibility with older devices

Requested features

2 requests
  • Ability to manually log sun sessions and vitamin D sources
  • Option to view upcoming day's sunrise/sunset times

Project Function

Not enough reviews yet to summarise bugs or requests.

In-app purchases

7 purchases

MyCircadianApp

Subscriptions4
  • Monthly7 Days trial$3.991 Month
  • Monthly1 Month trial$3.991 Month
  • Yearly1 Month trial$36.001 Year
Show 1 more
  • Yearly7 Days trial$36.001 Year
One-time3
  • Lifetime$99.00
  • Lifetime$179.00
  • Lifetime$199.00
None

Project Function

No in-app purchases

Questions

Is MyCircadianApp free?
MyCircadianApp is free to download, with in-app purchases available.
Is Project Function free?
Project Function is free to download, with no in-app purchases.
Do MyCircadianApp or Project Function have ads?
Neither MyCircadianApp nor Project Function shows ads.
Which is updated more often, MyCircadianApp or Project Function?
MyCircadianApp ships an update monthly, and Project Function every 6 weeks. Most recently, MyCircadianApp was updated on November 12, 2026 and Project Function on November 12, 2026.

Other comparisons