Comparison

Multiplier vs AONA Events

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

Head to head
About

Multiplier

This app automates complex calculations for predicting mature height, bone length, and limb length discrepancies in children. It simplifies manual methods, reducing calculation time and errors for various orthopedic and growth-related assessments.

Highlights
  • Predict mature height
  • Calculate bone length
  • Assess limb length discrepancy
  • Analyze growth remaining
  • Plot height on CDC charts
  • Scanogram calculations
  • Foot length analysis
Features
Read full description

The Multiplier App automates calculations to predict mature height and bone length in children. This method was created originally in Baltimore at the University of Maryland and subsequently developed at the International Center for Limb Lengthening (ICLL), Rubin Institute for Advanced Orthopedics (RIAO), Sinai Hospital of Baltimore. We have taught the Multiplier Method for more than 19 years at our annual Baltimore Limb Deformity Course (http://www.DeformityCourse.com). These calculations are typically performed by hand, using various formulae. Certain calculations are easy, but others involve more complicated formulae. Utilizing this app will reduce the time needed for these routine calculations and decrease errors. You need only input certain data (sex, age, length) and the app will calculate the answer by using the appropriate Multiplier formula. The Multiplier App will allow you to make the following calculations: LOWER EXTREMITY · Limb Length Discrepancy (LLD) (Congenital) · LLD (Developmental) · Growth Remaining · Bone Length · Timing of Angular Correction · Timing of Epiphysiodesis · Comprehensive (Congenital) LLD and Epiphysiodesis · Scanogram Calculations (Calculates femur/tibia lengths, overall limb length discrepancy, and amount/side of femur/tibia discrepancies) UPPER EXTREMITY · LLD (Congenital) · LLD (Developmental) · Growth Remaining · Bone Length Height and CDC Growth Charts (Calculates height at maturity, calculates height at every age, and plots the patient’s height and weight on the CDC growth charts) ACHONDROPLASIA · Height · Sitting Height · Leg Length Fetus (Calculates the length of tibia or femur at birth and maturity) FOOT · Foot Length · Foot Length Discrepancy · Foot Height · Foot Height Discrepancy Spine (Calculates sitting height at maturity) Oblique Plane Deformity (Calculates magnitude, orientation, and direction of an oblique plane deformity) Inclined Osteotomy (Calculates the rotational orientation and the vertical inclination of the osteotomy) This app also provides the following additional resources: · Bone Age: Elbow and Hand (Shows how to determine skeletal age by using radiographs of the elbow or hand) · Figures that show the standard measurements for the lower limb and foot · The multiplier formulae that the app uses to perform the calculations · Tables that show the multiplier values that are used in the formulae · Figures that show the Solomin Foot Analysis (Deformity correction planning for the midfoot, hindfoot, and ankle using reference lines and angles provided by Dr. Leonid Solomin) · Figures that show the development of the apophyses, epiphyses, and bones · Bibliography · User guide DISCLAIMER: No growth prediction method is 100% accurate; this App is not a substitute for sound and careful clinical judgment. PRIVACY POLICY: We respect the privacy of the people who use the International Center for Limb Lengthening apps. The Multiplier app does not collect, use, or distribute any data from the users.

About

AONA Events

Access all information for AO North America courses, including schedules, materials, venue details, and faculty bios. You can also access your CME directly within the application.

Highlights
  • View event schedules
  • Access course materials
  • Venue information
  • Faculty biographies
  • Direct CME access
Features
Read full description

The AO North America Event app is a resource for you while attending one of our courses. You can stay up to date and informed about our current and future events right at your fingertips. Designed as your single go-to source, you can: view schedules, course materials, venue information and faculty bios. You can access your CME directly from the app.

Screenshots

Multiplier4 screens
AONA Events4 screens

Verdict

The call

The clearest difference is monetization model: AONA Events at free against Multiplier's paid. AONA Events also leads on rating (5.0 vs 4.6) and update cadence (every 2 months vs every 6 months). Multiplier's advantage is ratings volume (24 vs 3). On price, ads, in-app purchases 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. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

AONA Events holds the better App Store score, 5.0 against 4.6. That said, the two scores are not equally well evidenced: Multiplier has 24 ratings behind it against 3, so its average is the more settled of the two. Written reviews point the same way: 83% of Multiplier's written reviews are positive against 100% of AONA Events's.

UpkeepUpdate frequency

Multiplier ships an update every 6 months, AONA Events every 2 months. The most recent releases landed on October 23, 2026 and October 21, 2026 respectively.

Scorecard5 real differences · 5 level
Multiplier versus AONA Events: the parameters behind the verdict, then further details
ParameterMultiplierAONA Events
PriceFreeFree
Rating4.6 (24 ratings)5.0 (3 ratings) — better
Positive reviews83.3% of reviews100.0% of reviews — better
Number of ratings24 — better3
Update frequencyEvery 6 monthsEvery 2 months — better
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13.012.2 — better
Further details — not scored
Size62 MB215 MB
Age rating12+12+
DeveloperLifeBridge HealthThe AO North America Inc

Customer experience

Multiplier

All ratings24 ratings
Positive95.8%
Neutral0.0%
Negative4.2%
Written reviews30 reviews
Positive83.3%
Neutral0.0%
Negative16.7%

AONA Events

All ratings3 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

Multiplier

No in-app purchases

None

AONA Events

No in-app purchases

Questions

Is Multiplier free?
Multiplier is free to download, with no in-app purchases.
Is AONA Events free?
AONA Events is free to download, with no in-app purchases.
Which has better reviews, Multiplier or AONA Events?
AONA Events is rated higher. Multiplier averages 4.6 out of 5 from 24 ratings, while AONA Events averages 5.0 from 3 ratings.
Do Multiplier or AONA Events have ads?
Neither Multiplier nor AONA Events shows ads.
Which is updated more often, Multiplier or AONA Events?
Multiplier ships an update every 6 months, and AONA Events every 2 months. Most recently, Multiplier was updated on October 23, 2026 and AONA Events on October 21, 2026.

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