This study presents a smartphone application, named「Vepi Tools」. This stand-alone type application is aiming at supporting on-site decision-making for animal health professionals. It provides basic calculations of epidemiology including estimating disease frequency, measuring associations using two-by-two table, calculating sample sizes to detect disease, and to estimate a mean or prevalence. Rationale and examples are available for each function. This study shows some use cases with this「Vepi Tools」application.