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How to Compare Medicare Plans in Washington State: A Step-by-Step Guide

By Michael Gurr · Published 2026-05-12 · Updated 2026-05-12

If you're approaching Medicare and staring at a stack of mailers, brochures, and TV ads, the options can feel genuinely overwhelming. Dozens of plan names. Hundreds of variations. Everyone claiming to be the best.

Here's the truth: comparing Medicare plans is not that complicated once you know what to look at — and in what order. This guide walks through it step by step, with Washington-specific context at each stage.

Step 1: Understand What You Already Have

Before comparing anything, get clear on the baseline.

When you enroll in Medicare, you automatically get Original Medicare — Parts A and B. Part A covers hospital care. Part B covers doctor visits, outpatient services, and lab work. This is the foundation everything else builds on.

Original Medicare covers a lot — but it has gaps. There's no cap on the 20% you owe after your Part B deductible, and it doesn't cover prescriptions, dental, vision, or hearing. Most Washington residents add coverage to fill those gaps.

What this means in plain English: You're not choosing between Original Medicare and something else. You're choosing what to add on top of it.

Step 2: Choose Your Coverage Path

There are two main directions you can go:

Path A — Original Medicare + Supplement + Part D

You keep Original Medicare and add a Medigap plan to cover most of what Medicare doesn't pay, plus a separate Part D plan for prescriptions. This path gives you broad provider access and predictable costs.

Path B — Medicare Advantage (Part C)

A private plan bundles Parts A, B, and usually D into one package. Most have low or $0 premiums. You use a plan network and pay copays when you use care.

This is the most important decision in the comparison process. Once you know which path fits your situation, the rest of the comparison gets much simpler.

A few questions that help you decide:

• Do you have specific doctors you want to keep? (Supplement = any Medicare provider; Advantage = plan network)
• Do you travel frequently? (Supplement covers nationwide; most Advantage plans are geographically tied)
• Do you want predictable monthly costs or lower upfront premiums with some variability?

Step 3: Make a List of Your Doctors and Check Networks

Before you look at a single plan, write down every provider you want to keep:

• Your primary care doctor
• Any specialists you see regularly
• Your preferred hospital or health system
• Any surgeons or providers you're currently treating with

For Medicare Advantage plans, provider networks vary significantly across Washington counties. A plan that covers MultiCare providers in Pierce County may not cover Virginia Mason providers in Seattle. Check each plan's directory before you assume your doctors are covered.

For Medicare Supplement plans, this step is simpler: if a provider accepts Medicare, they accept your Supplement. No network lookup needed.

What this means in plain English: Don't assume your doctor is in the network. Verify it. Plans change their networks every year, and discovering a provider isn't covered after you're enrolled is a frustrating and expensive surprise.

Step 4: List Your Medications and Check the Formulary

Every Part D and Medicare Advantage plan has a formulary — the list of drugs it covers and at what cost tier. The same medication can be a $5 generic on one plan and a $90 Tier 3 drug on another.

Before comparing costs, go to Medicare Plan Finder and enter your medications. The tool will show you the annual drug cost for each plan based on your specific prescriptions.

Things to check:

• Is your medication on the formulary at all?
• What tier is it?
• Does the plan require prior authorization or step therapy for any of your drugs?
• Which pharmacy do you use — is it in the plan's preferred network?

What this means in plain English: Your drug costs can vary by hundreds or thousands of dollars per year depending on which plan you choose. This step is worth 20 minutes of your time.

Step 5: Compare Total Annual Costs — Not Just Premiums

This is where most people make their biggest comparison mistake.

When evaluating any plan, calculate the total annual cost — not just the monthly premium. Include:

• Monthly premiums (plan premium + Part B premium)
• Annual deductibles
• Expected copays and coinsurance based on how often you typically use healthcare
• Estimated drug costs from your formulary check
• The plan's annual out-of-pocket maximum (for Advantage plans)

Run the numbers for your situation specifically — not based on a plan's advertising.

Step 6: Check Washington-Specific Advantages

Washington has two rules that work in your favor and aren't available in most other states:

Community rating: Washington requires Medigap insurers to charge the same premium regardless of your age at 65 or older. You don't pay more just because you're 71 instead of 65.

Open enrollment for Medigap: In Washington, you can switch from one Supplement plan to the same plan letter at any time without answering health questions. If your Plan G premium increases, you can shop for a lower-priced Plan G from another carrier without starting over medically.

Step 7: Use Medicare Plan Finder — But Understand Its Limits

Medicare's free Plan Compare tool is the best starting point for comparing plans available in your ZIP code. Enter your medications, your providers, and your pharmacy for a side-by-side comparison with estimated annual costs.

What it does well: broad comparison of plans in your area, drug cost estimates, provider lookup.

What it doesn't do: tell you which plan is right for your specific situation, explain the Supplement vs. Advantage tradeoffs, or account for Washington's community rating advantage.

What this means in plain English: Plan Finder is a research tool, not a decision tool. Use it to gather information, then apply the framework in this guide to make the actual decision.

Frequently Asked Questions

Comparing Medicare plans doesn't have to feel overwhelming. Work through these steps in order and the right choice for your situation usually becomes clear.

If you'd like a second set of eyes on your specific situation, I'm happy to walk through it with you.

This article is for educational purposes. For official Medicare information, visit medicare.gov.