Comparison

kegg vs Chart35

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

Head to head
About

kegg

This medical-grade device offers accurate fertility tracking by analyzing cervical fluid in just two minutes daily. It helps identify fertile windows for conception and provides insights into ovulation, while also offering guided pelvic floor exercises for health and recovery.

Highlights
  • Medical-grade fertility tracking
  • Cervical fluid analysis
  • Fertile window identification
  • Ovulation probability insights
  • Guided kegel exercises
  • Pelvic floor health optimization
Features
Read full description

Meet kegg® - a medical-grade fertility tracking device that gives you accurate and personalized fertility tracking through cervical fluid in just 2 minutes a day. Clinically validated fertility monitor Constructed of medical-grade silicone, kegg uses advanced sensing technology to detect the dynamic shifts in your fertility. Track Your Key Fertility Metric Maximize your chances of pregnancy by accurately detecting fertile versus non fertile cervical mucus so you can time your efforts with precision. Daily Fertility Insights Your Fertility and Cervical Mucus Score helps you identify your most fertile days, while the ovulation probability helps you see when ovulation may occur. Guided Kegel Exercises Optimize your pelvic floor health for labor and postpartum recovery using kegg’s kegel routines. CONNECT WITH KEGG: + Web:http://www.kegg.tech/ + Facebook: @kegg.tech + Instagram: @kegg_tech + Private community: https://www.facebook.com/groups/keggcommunity/ GET HELP: If you have any questions about the kegg device or the kegg app, read our FAQ at https://kegg.tech/faq or message us at www.kegg.tech/support

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

kegg4 screens
Chart354 screens

Verdict

The call

The clearest difference is update cadence: Chart35 at every 6 days against kegg's every 3 weeks. Chart35 also leads on device support (4 vs 2). On price, ads, in-app purchases and iOS requirement 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. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

kegg ships an update every 3 weeks, Chart35 every 6 days. The most recent releases landed on September 25, 2026 and September 19, 2026 respectively.

Scorecard2 real differences · 8 level
kegg versus Chart35: the parameters behind the verdict, then further details
ParameterkeggChart35
PriceFreeFree
Rating4.0 (140 ratings) — better—
Positive reviews76.1% of reviews—
Number of ratings140 — better—
Update frequencyEvery 3 weeksEvery 6 days — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaid—
DevicesiPhone, iPodiPhone, iPad, iPod, Apple Watch — better
Requires iOS15.115.0 — better
Further details — not scored
Size52 MB5 MB
Age rating12+4+
DeveloperLady Technologies, Inc.Stephens Page LLC

Bugs and requests

kegg

Reported bugs

4 issues
  • App freezes and crashes frequently
  • Syncing issues between device and app
  • Fertility predictions do not align with other methods
  • Constant logout prompts disrupt user experience

Requested features

4 requests
  • Add ability to track period and symptoms
  • Improve app design and user experience
  • Provide more detailed data analysis and insights
  • Integrate with other fertility tracking apps

Chart35

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

kegg

No in-app purchases

None

Chart35

No in-app purchases

Questions

Is kegg free?
kegg is free to download, with no in-app purchases.
Is Chart35 free?
Chart35 is free to download, with no in-app purchases.
Do kegg or Chart35 have ads?
Neither kegg nor Chart35 shows ads.
Which is updated more often, kegg or Chart35?
kegg ships an update every 3 weeks, and Chart35 every 6 days. Most recently, kegg was updated on September 25, 2026 and Chart35 on September 19, 2026.

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