Web-Based Sample Size Calculator for Structural Equation Modelling

Planning studies involving confirmatory factor analysis (CFA) and structural equation modelling (SEM) requires determining adequate sample sizes. Available methods for this include rule-of-thumb, Monte Carlo simulation and sample size formulas. Manual calculations using sample size formulas are tedious and prone to errors, making software-based solutions preferable. This article introduces a user-friendly, web-based calculator for sample size determination in CFA and SEM studies. The calculator utilises established formulas based on the root mean squared error of approximation and comparative fit index. The development process and core functionalities are discussed, along with demonstrations using common CFA and SEM examples. Additionally, the author also compare this calculator with other available web-based sample size calculators for SEM.