This calculator is intended to be used to estimate the threshold time-weighted average per- and polyfluoroalkyl substance (PFAS) concentration that is quantifiable using diffusive gradients in thin-films (DGT) passive samplers. This DGT calculator may be used to estimate the required deployment time to allow for sufficient PFAS adsorption in field deployments by adjusting deployment time, number of DGT devices or exposed gel area, and the final methanol extract volume. Calculations are based on the DGT equation and are estimates only.