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

Health Insurance →Medicare →

Tip

Glossary definitions are educational. Always check your own policy language — insurers can define common terms differently from one another. When in doubt, request a written explanation from your agent.

Related terms

Drug TierDrug tiers rank medications from cheapest (generics) to most expensive (specialty drugs), with your copay or coinsurance rising as tiers increase.Prior AuthorizationPrior authorization is an insurer's cost-control mechanism that can delay care if approval is not obtained in advance.Step TherapyStep therapy protocols require patients to try and fail on cheaper drugs or treatments before the insurer will cover a more expensive option.Medicare Part DMedicare Part D covers prescription drugs and features a $2,100 out-of-pocket cap in 2026, ending the coverage gap that previously left beneficiaries with full costs.

Related guides

Source: Cover Forge USA editorial team|Last verified: May 2026|Methodology
Definitions are educational and may be simplified. Always refer to your policy contract and consult a licensed agent for terms that affect coverage decisions.
CF

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 June 2026

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.

← Back to Insurance Glossary (355 terms)