Medication Adherence Calculator

Medication adherence -- taking a prescribed medication as directed -- is commonly tracked in pharmacy and clinical settings using pill counts rather than self-report, because patients tend to overestimate how consistently they've taken a medication. This calculator uses a simple pill-count method: it compares how many pills you should have taken by now (based on the days supply and days since your last refill) against how many pills are actually missing from the bottle (dispensed minus remaining). The ratio of pills actually taken to pills expected to have been taken, expressed as a percentage and capped at 100%, is your adherence rate.

Clinical research on chronic disease medications commonly treats an adherence rate at or above 80% as the threshold associated with meaningfully better treatment outcomes, though the exact cutoff that matters varies by drug class and condition. The calculator also converts your missed pill count into missed days of therapy, which is often a more actionable number to discuss with a pharmacist or prescriber than a percentage alone -- "you've missed roughly four days of doses" is easier to act on than "your adherence is 87%." Pill-count adherence has real limitations: it can't detect pills that were taken out of the bottle but not actually swallowed, doesn't account for dose-timing problems within a day, and assumes the days-supply and refill-date figures you enter are accurate.