Comparison

OB Wheels vs OB Calc (cloud)

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

Head to head
About

OB Wheels

This app calculates due dates, gestational age, and reconciles sonogram and LMP dates using a digital OB wheel and calendar. It offers a familiar interactive wheel for precise date calculations, accounting for leap years.

Highlights
  • Calendar calculator for EDD/EDC
  • Gestational age calculation
  • Interactive digital OB wheel
  • Reconciliation of due dates
  • Leap year accuracy
Features
Read full description

Does the world need another OB-wheel-due-date-calculator app? You bet! OB Wheels combines three things that clinicians need to derive all the dates necessary in pregnancy care, and no other app has this combination. It contains a calendar calculator to determine EDD (EDC) from LMP or from a sonogram report. The calendar calculator also provides gestational age (EGA) as of any date for a given EDD or LMP. Because the calculator works off the real calendar, it is accurate for leap years too. Then for all of you who miss your cardboard OB wheel, the app contains one which you can rotate, pinch and zoom, and generally play with just like a regular cardboard wheel. It's a little tricky to learn how to plant two fingers and rotate them rather than pinch-and-zoom to get rotation versus resizing. But the wheel works and it is accurate, especially so because you can zoom in to be sure where the little date hash lines lie. Finally, the app notes the most recent committee opinion scheme from ACOG on how one might reconcile due dates from LMP and sonograms to arrive at a single final EDD. To my knowledge, the scheme is authority-based and no better or worse than other schemes, but my practice and my learners need a single clear scheme, so this app includes one for easy reference. As an educator and clinician myself, I am grateful for feedback. Email me via the contact email at my website.

About

OB Calc (cloud)

This medical app helps obstetricians efficiently calculate key patient test date windows. It offers multiple calculation methods and allows for saving patient data and generating PDF reports. A free trial is available, followed by a subscription for full access.

Highlights
  • LMP, EDC, Ultrasound, CRL, and IVF calculations
  • Customizable test date ranges
  • Cross-device data syncing
  • PDF report generation
  • Save individual patient data
Features
Read full description

While similar to a pregnancy wheel, OB Calc (cloud) is specifically designed by an obstetrician, for obstetricians. Finally obstetricians have an efficient and simple method to calculate the important test date windows for patients. CALCULATION METHODS • Last Menstrual Period (LMP) • Expected Delivery Date (EDC) • Sonogram Date and Fetal Age (Sonogram) • Crown Rump Length (CRL) • In Vitro Fertilization (IVF) Try the app for free for 7 days. A low monthly autorenewable subscription gives users access to premium features such as all calculation methods and saving of individual patient data. You can reach the developer directly at support@inpocketsolutions.com FEATURES • LMP, EDC, Ultrasound, CRL and IVF Method Calculations • Customize up to 15 tests, with date ranges • Data synced across multiple devices • Generate a PDF file • Save individual patient data CRL data reference : https://obgyn.onlinelibrary.wiley.com/doi/pdf/10.1002/uog.7654 Terms & Conditions: https://inpocketsolutions.com/terms ** Disclaimer Remember to test out the app on your specific device to ensure calculations are verified to your expectation.

Screenshots

OB Wheels4 screens
OB Calc (cloud)4 screens

Verdict

The call

The clearest difference is rating: OB Calc (cloud) at 5.0 against OB Wheels's 2.3. OB Calc (cloud) also leads on update cadence (every 3 months vs every 18 months). OB Wheels's advantage is in-app purchases (none vs 2) and review sentiment (20% vs 0%). On price, 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. OB Calc (cloud) sells 2 in-app purchases, starting at $2.99 per month. OB Wheels asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

OB Calc (cloud) holds the better App Store score, 5.0 against 2.3. Both are backed by a comparable volume of ratings — 15 and 5 respectively. Written reviews complicate that: 20% of OB Wheels's written reviews are positive against 0% of OB Calc (cloud)'s, so the app with the better star average is not the one people write more warmly about.

UpkeepUpdate frequency

OB Wheels ships an update every 18 months, OB Calc (cloud) every 3 months. Both last shipped on September 21, 2026.

Scorecard7 real differences · 3 level
OB Wheels versus OB Calc (cloud): the parameters behind the verdict, then further details
ParameterOB WheelsOB Calc (cloud)
PriceFreeFree
Rating2.3 (15 ratings)5.0 (5 ratings) — better
Positive reviews20.0% of reviews — better0.0% of reviews
Number of ratings15 — better5
Update frequencyEvery 18 monthsEvery 3 months — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree — betterFree with in-app purchases
DevicesiPhone, iPodiPhone, iPad, Mac — better
Requires iOS7.0 — better18.0
Further details — not scored
Size3 MB14 MB
Age rating17+4+
DeveloperJoshua D. steinbergGlen Botha

Customer experience

OB Wheels

All ratings15 ratings
Positive20.0%
Neutral13.3%
Negative66.7%
Written reviews10 reviews
Positive20.0%
Neutral10.0%
Negative70.0%

OB Calc (cloud)

All ratings5 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

In-app purchases

None

OB Wheels

No in-app purchases

2 purchases

OB Calc (cloud)

Subscriptions2
  • Monthly Subscription$2.991 Month
  • Premium (Annual)$29.991 Year

Questions

Is OB Wheels free?
OB Wheels is free to download, with no in-app purchases.
Is OB Calc (cloud) free?
OB Calc (cloud) is free to download, with in-app purchases available.
Which has better reviews, OB Wheels or OB Calc (cloud)?
OB Calc (cloud) is rated higher. OB Wheels averages 2.3 out of 5 from 15 ratings, while OB Calc (cloud) averages 5.0 from 5 ratings.
Do OB Wheels or OB Calc (cloud) have ads?
Neither OB Wheels nor OB Calc (cloud) shows ads.
Which is updated more often, OB Wheels or OB Calc (cloud)?
OB Wheels ships an update every 18 months, and OB Calc (cloud) every 3 months. Most recently, OB Wheels was updated on September 21, 2026 and OB Calc (cloud) on September 21, 2026.

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