DeAnnCNV, an online tool, designed for precise Detection and Annotation of Copy Number Variations (CNVs) from whole-exome sequencing (WES) data. DeAnnCNV can accurately infer the CNVs of each subject based on the methodology, we described in our previously published algorithm GPHMM. It can also extract CNVs shared among multiple subjects and can further copiously annotate them based on several supporting sources including known CNVs in dbVar, CNVs related genes, genetic phenotypes of CNVs in OMIM, tissue specific mRNA expression, functional enrichment analysis of these genes and their protein-protein interaction network.