This paper focuses on parameter uncertainty quantification (UQ) in specific absorption rate (SAR) calculation using a computer-aided design mobile phone model. The uncertainty in SAR calculation is quantified by three nonintrusive UQ methods: unscented transformation, stochastic collocation, and nonintrusive polynomial chaos. Their performances for the cases of one and two random variables are analyzed. To simplify the UQ procedure for the case of multiple uncertain inputs, it is demonstrated that uncertainties can be combined to evaluate the parameter uncertainty of the output. To quantify the relative importance of each uncertain input parameter with respect to the uncertainty of the output, the polynomial chaos based Sobol' indices method is used in SAR calculation for sensitivity analysis. The results of the investigations are presented and discussed.