Comparison

Fertility Friend FF Tracker vs Chart35

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

Head to head
About

Fertility Friend FF Tracker

This app helps women track their ovulation and fertile days with advanced charting tools. It provides personalized insights into your cycle, helping you understand your fertility signs and maximize your chances of conception. Millions of women trust it for accurate cycle analysis and pregnancy tracking.

Highlights
  • Ovulation detection
  • Fertile window prediction
  • BBT and cervical fluid tracking
  • Period and symptom logging
  • Interactive fertility charts
  • TTC educational library
  • Pregnancy monitoring
Read full description

Track ovulation with confidence with the gold standard fertility charting app, trusted for over 25 years. Fertility Friend helps to accurately find your most fertile days, understand your ovulation pattern, and learn more about your unique cycle. Join the millions of women who have used Fertility Friend while trying to conceive, including over 1 million who recorded positive pregnancy tests in the app. Track your period and key fertility signs (BBT, cervical fluid, OPKs, symptoms). Fertility Friend will automatically create your chart, highlight your fertile window, and provide personalized insights, including when ovulation likely occurred and when to test for pregnancy. Fertility Friend teaches you how to chart, what your signs mean, and gives you the confidence to never miss a fertile opportunity. What’s FREE: - We do not sell or share your data or display ads - 30-day trial of premium features (No credit card, no auto-charge) - Automatic ovulation detection - Use Fertility Friend’s advanced (default) accurate ovulation detector or choose ovulation detection based on the Fertility Awareness Method (FAM) - Interactive fertility chart with coverline and symptom display - Color-coded fertility calendar: see your period, fertile days, ovulation and more at a glance - Detailed and customizable data entry: period, BBT, OPK, CM, symptoms, meds, LH tests… - Sync with Apple Health and Oura (automatic import of temps, heart rate, sleep, and more) - Graphical cycle progress bar/ticker display - Daily data summary - Period tracking - Menstrual cycle statistics: cycle length, phase length, ovulation dates - Extensive TTC educational library: videos, lessons, quizzes, games, articles - Searchable gallery of 240,000+ shared cycles. - View real life BBT charts filtered by keywords - Sharing possibilities (optional) - Dark Mode and custom color themes - Companion access to FertilityFriend.com What’s PREMIUM (Highlights): - All Free features plus - Advanced fertility insights and analysis - More graphs & detailed interpretations - Enhanced data display on chart and calendar - Cycle comparison tools - Pregnancy Monitor - Pregnancy Tracker - Charts “Like Mine” gallery search - Stats display on Chart Gallery searches - Pattern detection - Private, supportive community - Additional expert tools developed over decades Fertility Friend offers unmatched experience, accuracy, and depth to help you understand your cycle with confidence. Important: This app provides educational estimates only and must not be used to avoid pregnancy or schedule medical procedures. Always consult your healthcare provider for medical advice.

About

Chart35

Features
Read full description

Chart35 is a private fertility-charting app for the Creighton Model FertilityCare System (CrMS). Record each day's observation, see your color-coded stamp and chart, and keep your record on your own device. YOUR DATA STAYS WITH YOU Chart35 is offline-first. Your observations live on your device and the app works with no connection. Account sync is optional. When you turn it on, your records are encrypted on your device before they are uploaded, so the server stores data it cannot read. CHART THE WAY YOU WERE TAUGHT - Color-coded stamps: red, green, white, and yellow, matching standard CrMS charting. - Observation codes for bleeding, mucus, and frequency, built from the codes you already use. - Peak Day and post-peak count tracking. - Chart and calendar views, with Normal, Compact, and Trend zoom to see one cycle or many at a glance. - Insights: cycle count, average cycle length, and a cycle-length trend at a glance. SHARE WITH YOUR PRACTITIONER Generate a read-only link to your chart for your FertilityCare Practitioner. The link is encrypted so the server cannot read the shared data, and you can revoke it at any time. BUILT FOR REVIEW Your notes stay private and are never included in a shared chart. You decide what syncs and what is shared. You can delete your account and data at any time. ABOUT THE METHOD Chart35 is a charting and record-keeping tool. It is not medical advice and does not interpret your fertility for you. The Creighton Model is learned with a certified FertilityCare Practitioner. Yellow-stamp (Base Infertile Pattern) use in particular should only follow a baseline established with your practitioner. To find a practitioner, see your instructor or a FertilityCare center. Chart35 is independent and is not affiliated with or endorsed by the Saint Paul VI Institute or the creators of the Creighton Model System. "Creighton Model" and "FertilityCare" refer to the method and are used to describe what the app charts.

Screenshots

Fertility Friend FF Tracker4 screens
Chart354 screens

Verdict

The call

The clearest difference is in-app purchases: Chart35 at none against Fertility Friend FF Tracker's 4. Chart35 also leads on device support (4 vs 2). Fertility Friend FF Tracker's advantage is ratings volume (7.4K vs 1). On price, rating, update cadence and ads 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. Fertility Friend FF Tracker sells 4 one-off in-app purchases. Chart35 asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Chart35 holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: Fertility Friend FF Tracker has 7.4K ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

Fertility Friend FF Tracker ships an update weekly, Chart35 every 6 days. Both last shipped on October 24, 2026.

Scorecard3 real differences · 7 level
Fertility Friend FF Tracker versus Chart35: the parameters behind the verdict, then further details
ParameterFertility Friend FF TrackerChart35
PriceFreeFree
Rating4.8 (7.4K ratings)5.0 (1 ratings) — better
Positive reviews78.1% of reviews—
Number of ratings7.4K — better1
Update frequencyWeeklyEvery 6 days — better
AdsNoNo
In-app purchasesYesNo — better
MonetizationFreemium—
DevicesiPhone, iPadiPhone, iPad, iPod, Apple Watch — better
Requires iOS16.615.0 — better
Further details — not scored
Size33 MB5 MB
Age rating17+4+
DeveloperTamtris Web Services Inc.Stephens Page LLC

Bugs and requests

Fertility Friend FF Tracker

Reported bugs

4 issues
  • Unable to create account
  • Randomly deleting custom data
  • Inaccurate ovulation predictions
  • Pregnancy data not transferring

Requested features

5 requests
  • Offline mode with data syncing
  • Integration with Apple Health
  • More affordable subscription options
  • Improved community features
  • Streamlined data entry process

Chart35

Not enough reviews yet to summarise bugs or requests.

In-app purchases

4 purchases

Fertility Friend FF Tracker

One-time4
  • 30 Days VIP Membership$10.99
  • 90 Days VIP Membership$21.99
  • 1 Year VIP - Special Rate$23.99
Show 1 more
  • 1 Year VIP Membership$45.99
None

Chart35

No in-app purchases

Questions

Is Fertility Friend FF Tracker free?
Fertility Friend FF Tracker is free to download, with in-app purchases available.
Is Chart35 free?
Chart35 is free to download, with no in-app purchases.
Which has better reviews, Fertility Friend FF Tracker or Chart35?
Chart35 is rated higher. Fertility Friend FF Tracker averages 4.8 out of 5 from 7.4K ratings, while Chart35 averages 5.0 from 1 ratings.
Do Fertility Friend FF Tracker or Chart35 have ads?
Neither Fertility Friend FF Tracker nor Chart35 shows ads.
Which is updated more often, Fertility Friend FF Tracker or Chart35?
Fertility Friend FF Tracker ships an update weekly, and Chart35 every 6 days. Most recently, Fertility Friend FF Tracker was updated on October 24, 2026 and Chart35 on October 24, 2026.

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