Key Takeaway

Medicare Part D prescription drug plans for 2027 vary widely in cost, coverage, and pharmacy networks. To find the best fit, list your current medications, use Medicare’s Plan Finder tool at Medicare.gov to compare formularies and total annual costs, verify your preferred pharmacy is in-network, and enroll during the October 15 to December 7 Annual Enrollment Period. The right plan depends on your specific prescriptions, not just the monthly premium.

Introduction

Medicare Part D covers prescription drugs through private insurance plans approved by Medicare. With dozens of plans available in most areas and significant differences in what they cover and what they cost, choosing the right Part D plan for 2027 requires a methodical comparison. Unlike Original Medicare (Parts A and B), Part D is optional but highly recommended if you take regular medications, since out-of-pocket drug costs can quickly exceed thousands of dollars per year without coverage.

Each Part D plan maintains its own formulary (list of covered drugs), sets its own premiums and cost-sharing amounts, and contracts with specific pharmacy networks. A plan that works well for one person may be expensive or impractical for another, depending on the medications they take. The 2027 plan year brings updated coverage rules, including changes to the coverage gap and out-of-pocket maximums, making an annual comparison essential even if you are satisfied with your current plan.

This guide walks through the concrete steps to compare Part D plans for 2027, from gathering your medication list to enrolling in the plan that offers the best combination of coverage and cost for your situation.

What You Will Learn

  • How to prepare your medication list for accurate plan comparison
  • How to use Medicare’s Plan Finder tool to filter and compare 2027 plans
  • What formulary tiers mean and why they matter for your costs
  • How to calculate true annual costs beyond the monthly premium
  • Why pharmacy networks affect your out-of-pocket spending
  • How to evaluate plan restrictions like prior authorization
  • When to enroll and what deadlines you must meet

Step 1: List Your Current Prescriptions

Start by creating a complete list of every prescription medication you currently take or expect to need in 2027. Include the exact drug name (brand or generic), dosage (such as 10 mg, 50 mg), and quantity you fill each month (such as 30 tablets, 90 capsules). This information appears on your prescription bottle labels and on receipts from your pharmacy.

If you take multiple medications, ask your pharmacist for a printout of your prescription history from the past 12 months. Most pharmacies can generate this report quickly and at no charge. The printout will show the precise details Part D plan comparison tools require, including National Drug Code (NDC) numbers that ensure accurate matches.

Do not skip medications you take only occasionally or seasonally. If you use an inhaler for allergies in spring or antibiotics for recurring infections, include them. Part D plan formularies vary, and a plan that covers your daily medications well may not cover these occasional needs, leaving you with high out-of-pocket costs when you need them.

For each medication, note whether you currently use the brand-name version or a generic equivalent, and whether your doctor has specified that brand is medically necessary. Plans almost always place generics in lower-cost tiers, so knowing your flexibility here helps you evaluate plan costs accurately.

Step 2: Use Medicare’s Plan Finder Tool

The official Medicare Plan Finder at Medicare.gov is the most reliable resource for comparing 2027 Part D plans available in your area (according to the Centers for Medicare & Medicaid Services, Medicare Plan Finder). The tool is updated annually with current plan details, premiums, formularies, and pharmacy networks, and it calculates personalized cost estimates based on your specific medications.

To begin, visit Medicare.gov/plan-compare and enter your ZIP code. The tool will display all Part D stand-alone plans and Medicare Advantage plans with drug coverage (MA-PD) available where you live. If you have Original Medicare (Parts A and B), focus on stand-alone Part D plans. If you are considering Medicare Advantage, compare MA-PD plans that bundle medical and drug coverage.

Next, enter each medication from your list into the tool. Type the drug name, select the correct dosage and form (tablet, capsule, liquid), and specify the quantity you fill per month. The tool will match your entries to its drug database. Complete this step carefully, as the cost estimates and formulary matches depend on accurate medication data.

Once you have entered all medications, the tool will rank plans by estimated total annual cost, combining premiums, deductibles, and your projected out-of-pocket costs for the drugs you entered. This ranking is more useful than sorting by premium alone, since a low-premium plan may place your drugs in high-cost tiers or require larger copayments.

Step 3: Compare Formularies and Drug Tiers

Every Part D plan maintains a formulary, the list of prescription drugs it covers. Formularies are organized into tiers, typically ranging from Tier 1 (lowest cost, usually preferred generics) to Tier 5 (highest cost, often specialty drugs). Your copayment or coinsurance amount depends on which tier your medication occupies.

Review the formulary for each plan you are considering to confirm it covers all your medications. The Plan Finder tool flags drugs that are not covered or that require prior authorization, but you should also download the plan’s complete formulary document (available on the plan’s website or through the Plan Finder) to check for restrictions.

Pay close attention to tier placement. Two plans may both cover your medication, but if Plan A places it in Tier 2 (low copay) and Plan B places it in Tier 4 (high coinsurance), your costs will differ significantly. For expensive medications, a difference of one or two tiers can mean hundreds of dollars per fill.

Formularies can change from year to year. Even if your current plan covered your medications in 2026, verify that the 2027 formulary still includes them and that they remain in the same tier. Plans must notify you of formulary changes that affect your drugs, but proactively checking during the Annual Enrollment Period ensures no surprises.

If a plan does not cover one of your medications, ask your doctor if a covered alternative exists. Many plans cover multiple drugs in the same therapeutic class, and switching to a covered equivalent may be medically appropriate and far less expensive than paying out-of-pocket for a non-covered drug.

Step 4: Calculate Total Annual Costs

The monthly premium is only one component of your total Part D cost. To compare plans accurately, estimate your total annual spending, which includes the premium, the annual deductible, and your out-of-pocket costs for each medication throughout the year.

The Plan Finder tool provides a total annual cost estimate for each plan based on the medications you entered. This estimate accounts for the deductible phase (you pay the full cost until you meet the deductible), the initial coverage phase (you pay copays or coinsurance), and the coverage gap or catastrophic phase if your total drug costs are high.

For 2027, the standard Part D deductible is capped at a maximum set by Medicare (as of October 2026, the 2027 deductible cap had not yet been published by CMS, but it is typically adjusted annually for inflation and announced in the fall). Not all plans charge the full deductible; some have lower deductibles or no deductible at all, which benefits enrollees who fill prescriptions early in the year.

If you take expensive medications or multiple prescriptions, you may reach the coverage gap (sometimes called the donut hole), a phase where cost-sharing changes until you hit the catastrophic coverage threshold. The Inflation Reduction Act has made changes to Part D cost-sharing, including a cap on out-of-pocket spending, but understanding how each plan structures costs in these phases remains important for accurate comparison.

Add the estimated annual premium (monthly premium multiplied by 12) to the projected out-of-pocket drug costs the Plan Finder calculates. The plan with the lowest total annual cost is usually the best financial choice, even if its monthly premium is higher than others.

Step 5: Check Pharmacy Networks

Part D plans contract with specific pharmacies to form their networks. Using an in-network pharmacy typically results in lower copays, while filling prescriptions at an out-of-network pharmacy (if the plan allows it at all) often means paying significantly more or the full retail price.

Identify the pharmacies you prefer to use, whether a national chain, an independent local pharmacy, or a mail-order service. Then verify that each plan you are considering includes those pharmacies in its network. The Plan Finder tool lists preferred and standard network pharmacies for each plan.

Many plans designate certain pharmacies as preferred, offering even lower copays than standard network pharmacies. If your usual pharmacy is preferred under one plan but only standard under another, the difference in copays may be substantial over a year, especially for medications you refill monthly.

Mail-order pharmacies often provide a 90-day supply at a lower per-dose cost than 30-day retail fills, which can reduce your annual spending if you take maintenance medications. Check whether the plans you are comparing offer mail-order options and compare the 90-day mail-order cost to three 30-day retail fills.

If you travel frequently or spend part of the year in a different state, confirm that the plan’s pharmacy network extends to those areas. Some plans have strong networks in certain regions but limited options elsewhere, which can create access problems if you need to fill a prescription while away from home.

Read also: Medicare Open Enrollment 2026: Key Decisions to Make in the US Before December 7

Step 6: Review Plan Restrictions and Coverage Details

Beyond formularies and costs, Part D plans may impose restrictions on certain medications that affect your ability to fill prescriptions quickly and conveniently. The two most common restrictions are prior authorization and step therapy.

Prior authorization requires your doctor to get plan approval before the plan will cover a specific drug, typically because the medication is expensive or because less costly alternatives exist. If one of your medications requires prior authorization, expect a delay of several days to a week while your doctor submits medical justification and the plan reviews it. For ongoing medications, this is usually a one-time process per year, but for new prescriptions it can be inconvenient.

Step therapy requires you to try a lower-cost medication first (such as a generic) and demonstrate that it does not work before the plan will cover a higher-cost alternative (such as a brand-name drug). If you are already stable on a medication that requires step therapy under a new plan, your doctor can often request an exception by documenting your treatment history.

Quantity limits restrict how much of a medication you can fill at once, such as 30 tablets per 30 days. These limits are common for medications that carry abuse potential or for expensive drugs where the plan wants to ensure appropriate use. If you need a larger supply (for example, if you are traveling), you may need to request an override.

The Plan Finder tool and each plan’s formulary document indicate which drugs have restrictions. If several of your medications require prior authorization under a particular plan, consider whether the administrative burden justifies any cost savings, or whether a plan with fewer restrictions might be more practical even at slightly higher cost.

Step 7: Review Star Ratings and Plan Quality

Medicare assigns Star Ratings to Part D plans based on quality measures such as customer service, member satisfaction, and how well the plan manages drug safety and adherence. Ratings range from one to five stars, with five being the highest.

While cost and formulary coverage should be your primary criteria, Star Ratings offer insight into how well a plan performs operationally. A plan with low ratings may have poor customer service, difficulty resolving coverage issues, or high rates of member complaints. A plan with high ratings generally delivers a smoother experience when you need help or encounter a problem.

You can view Star Ratings for each plan in the Plan Finder tool results. Plans with 4 or 5 stars are typically well-regarded. If two plans are similar in cost and coverage, the one with the higher Star Rating is usually the better choice for overall service quality.

Step 8: Enroll During the Annual Enrollment Period

The Medicare Annual Enrollment Period for 2027 coverage runs from October 15 to December 7, 2026. During this window, you can enroll in a new Part D plan, switch from one plan to another, or drop Part D coverage entirely (though dropping coverage without creditable alternative coverage may result in a late enrollment penalty if you rejoin later).

If you are new to Medicare, you have a seven-month Initial Enrollment Period surrounding your 65th birthday (three months before, your birthday month, and three months after) to enroll in Part D without penalty. If you miss this window and do not have creditable prescription drug coverage from another source (such as employer coverage), you will face a late enrollment penalty that increases your premium permanently.

To enroll, you can complete the process online through the plan’s website, call the plan directly, or contact Medicare at 1-800-MEDICARE. Enrollment takes effect January 1, 2027, as long as you enroll by the December 7 deadline.

If your circumstances change during the year (you move, you lose other coverage, you qualify for Extra Help, or your plan is discontinued), you may qualify for a Special Enrollment Period that allows you to change plans outside the Annual Enrollment Period.

Practical Tips for Choosing the Right Part D Plan

Focus on total annual cost, not just the premium. A plan with a $10 monthly premium may cost you $2,000 per year after deductibles and copays, while a plan with a $50 monthly premium may cost $1,200 total if it covers your drugs at lower tiers.

Reevaluate your plan every year. Formularies, premiums, and networks change annually, and the plan that was best in 2026 may not be best in 2027. Foundational planning resources such as Principles of Finance (OpenStax, Rice University) emphasize the importance of reviewing insurance coverage regularly to ensure it continues to meet your needs and budget.

If your drug costs are high, check whether you qualify for Extra Help (also called the Low-Income Subsidy), a federal program that reduces Part D premiums, deductibles, and copays for people with limited income and resources. Apply through the Social Security Administration or your state Medicaid office.

Keep your medication list current. If your doctor adds, changes, or discontinues a medication, update your information in the Plan Finder tool to ensure your plan comparison reflects your actual needs.

Common Mistakes to Avoid

Choosing a plan based solely on the lowest premium is the most common error. Low-premium plans often have high deductibles, place common drugs in expensive tiers, or exclude certain medications entirely, leading to higher total costs.

Assuming your current plan is still the best option without comparing can cost you hundreds of dollars. Plans adjust their formularies, tier placements, and premiums every year, and a plan that covered your medications well in 2026 may not be competitive in 2027.

Forgetting to check whether your pharmacy is in-network can result in surprise out-of-network charges. Always verify pharmacy network status before enrolling.

Ignoring plan restrictions like prior authorization and step therapy can create hassles when you try to fill a prescription, even if the drug is technically covered. Review the formulary details for each of your medications, not just whether the plan lists them.

Waiting until the last days of the enrollment period to compare plans can leave you rushed and more likely to make a hasty decision. Start your comparison in mid-October to allow time to research, consult your doctor if needed, and enroll with confidence.

Frequently Asked Questions

Can I change my Part D plan after January 1? In most cases, you can only change plans during the Annual Enrollment Period (October 15 to December 7) or if you qualify for a Special Enrollment Period due to a life event such as moving or losing other coverage.

What happens if my plan drops one of my medications from its formulary mid-year? If your plan makes a negative formulary change that affects a drug you are currently taking, the plan must notify you and continue to cover the drug for the rest of the current year (or offer a transition supply if the change is immediate). You can file an exception request or switch to a different plan during the next Annual Enrollment Period.

Do I need Part D if I have retiree health coverage? Check whether your retiree coverage is creditable (at least as good as Medicare Part D). If it is, you can delay enrolling in Part D without penalty. If it is not creditable, you should enroll in Part D during your Initial Enrollment Period to avoid future penalties.

How do I know if I qualify for Extra Help? Extra Help eligibility is based on income and resources. For 2027, individuals with annual income below approximately $23,000 and resources below about $17,220 may qualify (exact figures are adjusted annually). Apply through Social Security or your state Medicaid office.

Conclusion

Comparing Medicare Part D prescription drug plans for 2027 takes time, but the effort can save you significant money and ensure your medications remain affordable and accessible throughout the year. By listing your prescriptions, using Medicare’s Plan Finder tool to calculate total costs, verifying formulary coverage and pharmacy networks, and enrolling during the Annual Enrollment Period, you can select the plan that best fits your health needs and budget. Plan details change every year, so make this comparison an annual habit to ensure you continue to have the coverage you need at the best available price.

Financial and Coverage Disclaimer: This article provides general educational information about comparing Medicare Part D prescription drug plans and is not personalized insurance, financial, or medical advice. Part D plan availability, formularies, premiums, deductibles, cost-sharing amounts, pharmacy networks, and coverage rules vary by plan and change annually. The information presented reflects general Part D program structure as of October 2026; verify current plan details, costs, and enrollment deadlines using the official Medicare Plan Finder at Medicare.gov or by contacting Medicare directly at 1-800-MEDICARE before making coverage decisions. Coverage rules, drug tier placements, and out-of-pocket costs vary by plan and by your specific medications. Consult a licensed insurance agent, your doctor, or a State Health Insurance Assistance Program (SHIP) counselor for personalized guidance based on your individual health needs, prescriptions, and financial situation.