Multiplier Mobile App

Predict a child's height or limb length discrepancy at maturity with the free Multiplier app!


Download Multiplier from the App Store or Google Play

Multiplier is a mobile app that 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 of the Rubin Institute for Advanced Orthopedics at Sinai Hospital of Baltimore. There have been over 102,400 downloads of the Multiplier app since it was released in 2011.

We have taught the Multiplier Method for more than 19 years at our annual Baltimore Limb Deformity Course. These calculations are typically performed by hand, using various formulas. Certain calculations are easy, but others involve more complicated formulas. Utilizing this App will reduce the time needed for these routine calculations, and decrease errors. You need only input the values about a patient (sex, age, length) and the App will execute the required Multiplier formula. Watch this video to see the Multiplier app in action:

Screenshot of a video tutorial demonstrating how to use the Multiplier app

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) Limb Length Discrepancy and Epiphysiodesis
  • 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
    • Length of tibia or femur at birth and maturity
  • Foot
    • Foot Length
    • Foot Length Discrepancy
  • Spine
    • Sitting Height at Maturity
  • Bone Age: Elbow
    • Shows a radiographic scoring system to determine skeletal age
  • Bone Age: Hand
    • Shows you how to use radiographic criteria to determine skeletal age
  • Oblique Plane Deformity
    • Calculates magnitude, orientation, and direction of an oblique plane deformity
  • Inclined Osteotomy Rotation Angle
    • Calculates the rotational orientation and the vertical inclination of the osteotomy

This app also provides the following additional resources:

  • Figures that show the standard measurements for the lower limb and foot
  • Multiplier formulae that the app uses to perform the calculations
  • Tables that show the values that are used in the multiplier formulae
  • 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 International Center for Limb Lengthening apps. The Multiplier app does not collect, use or distribute any data from the users.

Updates: To ensure that you are among the first to know of any Multiplier updates, please follow our Limb Length Apps Facebook page.