We present PurEst, a statistical framework that uses genome-wide DNA methylation data as the only input to first estimate tumor purity of samples and then adjust DNA methylation values of individual CpGs with respect to tumor purity to better reflect somatic changes in tumor cells and improve biological inference. Here we have added scripts and reference data for calculating tumor purity and adjusting Illumina 450/850K DNA methylation beta values. Updated scripts can be found on https://github.com/StaafLab/PurEst.