Multiplier vs AONA Events
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
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.
- Predict mature height
- Calculate bone length
- Assess limb length discrepancy
- Analyze growth remaining
- Plot height on CDC charts
- Scanogram calculations
- Foot length analysis
Read full descriptionHide 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.
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.
- View event schedules
- Access course materials
- Venue information
- Faculty biographies
- Direct CME access
Read full descriptionHide 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
Verdict
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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
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.
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.
| Parameter | Multiplier | AONA Events |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (24 ratings) | 5.0 (3 ratings) — better |
| Positive reviews | 83.3% of reviews | 100.0% of reviews — better |
| Number of ratings | 24 — better | 3 |
| Update frequency | Every 6 months | Every 2 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13.0 | 12.2 — better |
| Further details — not scored | ||
| Size | 62 MB | 215 MB |
| Age rating | 12+ | 12+ |
| Developer | LifeBridge Health | The AO North America Inc |
Customer experience
Multiplier
AONA Events
In-app purchases
Multiplier
No in-app purchases
AONA Events
No in-app purchases
Questions
Is Multiplier free?
Is AONA Events free?
Which has better reviews, Multiplier or AONA Events?
Do Multiplier or AONA Events have ads?
Which is updated more often, Multiplier or AONA Events?
Other comparisons















