A rigorous method is urgently needed to monitor and quantify species compositional shifts and reorganization of biodiversity across space and time. Nearly all biodiversity assessments are based on sampling data. When sampling is not complete, observed species diversity in a single assemblage depends on sampling effort and sample completeness. To compare diversity for more than one assemblage, it is necessary to standardize samples by sample size or coverage, through interpolation (rarefaction) or extrapolation, as implemented in iNEXT freeware. Beta diversity refers to the extent of differentiation in species composition among assemblages. Quantifying and measuring beta diversity based on sampling data is complicated, because observed beta diversity depends not only on sampling effort and sample completeness, but also on alpha (within-assemblage) and gamma (pooled assemblages) diversity. Under the framework of Hill numbers, this talk first reviews the iNEXT method and extends it to the iNEXT.BetaDiv  standardization for beta diversity via rarefaction and extrapolation. Alpha and gamma diversity are both assessed at the same level of sample coverage to formulate standardized, coverage-based beta diversity. The coverage-based standardization provides a statistical solution to remove the dependence of beta diversity on both gamma and alpha values. Real data are used for illustration.