Peritoneal dialysis therapy outcomes have been calculated for a variety of dwell times of peritoneal dialysis fluids in the peritoneal cavities of dialysis patients using kinetic modeling. The length of dwell time should not be the same for every patient, but should vary according to the patient condition and needs. Some patients have a potential for expressing greater ultrafiltrate into the dialysis fluid, and these patients can benefit from a longer dwell time, whereas other patients with less potential will not benefit from a longer dwell time. An optimal or peak time is observed for each peritoneal dialysis therapy outcome, such as ultrafiltrate volume rate, urea clearance (Kt/V), and creatinine clearance, while minimizing hydrocarbon absorption. These values and input parameters can be used to tailor the peritoneal dialysis dwell time for each patient, estimating the peak dwell time that will yield the best therapy outcome for each patient.