Understanding your insurance formulary can save you hundreds or even thousands of dollars per year on prescription medications. A formulary is your insurance plan's list of covered drugs, organized by tiers that determine your out-of-pocket cost. This guide walks you through reading and interpreting your formulary document, understanding tier structures, and identifying restrictions.
Key Facts
Check Your Specific Plan's Formulary
Coverage varies by plan. Use our formulary checker tool to look up your exact copay and restrictions.
Open Formulary CheckerSources and standards behind this page
Drug coverage in the United States is governed by published rules rather than by any one insurer's summary, and the sources below are the primary ones. They are linked so a reader can check a claim without taking this page's word for it.
- FDA Orange Book publishes the therapeutic-equivalence ratings that decide whether a generic may be substituted for a brand-name drug.
- FDA generic drug facts sets out what "generic equivalent" means and what a manufacturer must prove.
- CMS prescription drug coverage defines the rules a Medicare drug plan formulary must follow and how it may change mid-year.
- Medicare.gov drug coverage (Part D) states what a Part D plan is required to offer a member.
- CMS prescription drug appeals documents the coverage-determination and exception process when a drug is denied.
This page describes how coverage and formularies work. It is not medical advice, and a reader's own plan documents and prescriber decide what applies to them.
Frequently Asked Questions
Log in to your insurance company's member portal and look for Pharmacy Benefits, Drug List, or Formulary. Most insurers offer a searchable online tool and a downloadable PDF. You can also call the phone number on the back of your insurance card and ask for the formulary. During open enrollment, formularies are available on Healthcare.gov and state exchange websites.
Tiers indicate your cost-sharing level. Tier 1 is the cheapest (usually preferred generics at $0 to $15). Tier 2 is non-preferred generics. Tier 3 is preferred brands ($30 to $75). Tier 4 is non-preferred brands. Tier 5 or 6 is specialty drugs (often 25% to 33% coinsurance). The exact copay for each tier is listed in your plan's benefits summary.
PA means prior authorization: your doctor must get approval from your insurer before you can fill the prescription. ST means step therapy: you must try a cheaper drug first before the insurer covers the requested drug. QL means quantity limit: the plan limits how much of the drug you can get per fill or per month.
Related Resources
Get Formulary and Coverage Updates
Subscribe to receive alerts on formulary changes, new drug approvals, and insurance coverage updates.