Our methodology

Two separate kinds of numbers

The calculator compares prices you enter. The drug directory presents CMS National Average Drug Acquisition Cost (NADAC) data. We never turn those benchmarks into a claimed pharmacy quote or guaranteed saving.

Calculator arithmetic

Cash total = your cash quote + additional fees not already included. Difference per fill = insurance cost − cash total. A positive difference means cash costs less for this fill; a negative difference means insurance costs less. Annual difference = difference per fill × the number of identical fills you enter.

Annual figures assume unchanged prices, quantities, fees, and coverage. They do not model deductibles, benefit stages, taxes, clinical suitability, or future price changes. If comparing different days supplied, normalize the quotes first.

Snapshot and selection

Our selected dataset contains 319 descriptions, retrieved 2026-09-22. We query CMS for selected medication names, use the latest available as-of date, and retain one representative NDC for each normalized description. We keep the established atorvastatin example NDC when it exists; otherwise we select the lexicographically first NDC. This is not a representative sample of retail quotes, a complete NDC catalog, or inventory data.

Units and precision

Source rates retain five decimal places in the directory. EA means each, ML means milliliter, and GM means gram. Package size matters. A per-unit value is not necessarily the price for a tablet, device, bottle, pen, or course of treatment.

Freshness and limitations

Each record displays its as-of date. Rebuilding the website does not make source records newer. A snapshot more than 14 days old is flagged in the browser. Static pages retain their dates even without JavaScript. Missing descriptions, new products, discontinued products, and other manufacturers may not appear.

Commercial independence

Paid links do not change calculations, source values, or provider order. We do not publish fabricated coupon discounts, pharmacist review credentials, customer testimonials, or pharmacy rankings.

Download the data · Editorial policy