Health Insurance
Formulary
A formulary determines which medications your insurance covers and at what cost-sharing level, making it critical to review before choosing a plan.
Last reviewed: May 2026 · Editorial methodology
Definition
A formulary, also called a drug list, is the comprehensive list of prescription medications that a health insurance or Medicare Part D plan agrees to cover. Drugs are grouped into tiers — typically ranging from generic drugs at the lowest cost to specialty biologics at the highest — with each tier carrying a different copay or coinsurance requirement. Formularies are not static: plans can add, remove, or reclassify drugs mid-year with proper notice to members. If your medication is not on the formulary, you may pay full price, request a formulary exception, or pursue a medically necessary step therapy process. When comparing ACA marketplace or Medicare plans, always check whether your specific drugs and dosages appear on each plan's formulary before enrolling. Medicare Part D plans are required to cover at least two drugs in each therapeutic category, but the specific products and their tier placement vary widely by plan.
Where this term matters
💡 Tip
Related terms
Related guides
Cover Forge USA Editorial Team
Editorial Lead
This article was researched and written by the Cover Forge USA editorial team against federal sources (NAIC, CMS, FEMA, DOL, SSA, state DOIs) and standard policy forms. Bylines organize content by topic — they do not assert individual licensure. See our editorial-policy for details.
Reviewed 2026-06-14
Get Insurance Rate Alerts
We monitor rate filings in all 50 states. Get notified when rates change in your area — and discover new ways to save.
- ✓State-specific rate change alerts
- ✓Seasonal enrollment deadline reminders
- ✓Expert tips to lower your premiums
- ✓New coverage options in your state
Free forever. Unsubscribe with one click. No spam, ever.
Important Disclaimer
This site provides general educational information only and is not a substitute for professional insurance advice. All rates, data, and coverage details are estimates and may not reflect your actual premiums. Insurance availability and pricing vary by state, insurer, and individual risk factors. Always consult a licensed insurance professional in your state before making coverage decisions.