PERSENT is a perturbation and sensitivity calculation code for conventional assembly homogenized diffusion and transport problems. It is built on the VARIANT option of DIF3D. For perturbation, calculations can be done that consider typical material and cross section perturbations. For sensitivity calculations, users can compute eigenvalue, reaction rate, reaction rate ratio, power fraction, reactivity worth, prompt neutron lifetime, and beta effective sensitivities to the microscopic reactions: gamma, alpha, proton, deuteron, tritium, fission, nu, and P0 & P1 scatter cross sections.