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What Medigap costs in Washington, and what decides the price

By Vadim Marusin, licensed Medicare insurance agent in Washington (WAOIC #1365574). Insurer data checked against the state chart current as of October 8, 2026.

Washington is one of the few states where your age doesn't change your Medigap premium. Your plan letter, your insurer and how you pay do. Here's how to think about the whole bill, not just the monthly premium.

Mount Rainier above a subalpine lake and evergreen meadow — Mount Rainier above a subalpine lake. Photo: Unsplash

The short answer

Your Medigap cost in Washington depends on three things: the plan letter you choose, the insurer you buy from and discounts for a spouse or for how you pay. It does not depend on your age, your health once you're accepted, or which Washington county you live in. Each insurer charges every policyholder 65 and older the same premium for the same plan, a rule called community rating (RCW 48.66.045).

This site doesn't publish insurer premiums. Premiums change through the year as insurers get new rates approved, and a quote from a licensed agent or the insurer is the only reliable number. What we can show you is everything that drives the price, and the costs you pay besides the premium.

What changes the premium

The plan letter. The more a plan covers, the more it costs. Plan G costs more than Plan N, which costs more than high-deductible Plan G. Plan F, where you can still buy it, usually costs more than Plan G by more than the $283 difference in coverage.

The insurer. Because every insurer's Plan G pays the same benefits, the price difference between insurers is pure price. In Washington, the spread between the lowest and highest Plan G premium on the state chart is wide enough that shopping is worth an hour of your time.

Discounts. Washington allows only two kinds: a household discount when a spouse or partner also has a policy with the same insurer, and discounts for paying by automatic bank draft or paying annually. Ask each insurer what it offers.

Rate increases. Insurers can raise premiums for everyone in a plan after the Office of the Insurance Commissioner approves a rate filing. The state chart shows each insurer's current rate effective date. See Medigap rate increases in Washington.

What doesn't change it

Your age. A 66-year-old and a 92-year-old pay the same for the same plan from the same insurer. In most states, older buyers pay more.
Your county. An insurer's premium is the same everywhere it sells in Washington. What differs by county is which insurers sell there. Find your county.
Your health, once you're accepted. Insurers can't raise your premium because you got sick.

The rest of the bill

A Medigap premium is one of three or four health costs on Medicare:

Source: CMS 2026 Medicare amounts.
Cost	2026 amount	Who pays it
Part B premium	$202.90 a month in 2026 (more at higher incomes)	Everyone with Part B
Part A premium	$0 for most people with 40 quarters of work	Most people
Medigap premium	Set by your insurer and plan letter; same at any age in Washington	If you buy Medigap
Part D premium	Set by your drug plan; out-of-pocket drug costs capped at $2,100 in 2026	If you add drug coverage
Your share of care	Depends on your plan letter (see below)	When you use care

Compare plans on what you'd pay in a full year, not on premium alone. For two plans, add up:

Twelve months of premium.
The most you could owe for covered care under that plan (table below).
What you'd realistically use: Plan N copays are up to $20 per office visit and up to $50 per ER visit that doesn't lead to admission.

2026 Medicare amounts, premiums not included. Plan N has no yearly cap on its copays or excess charges. Source: CMS 2026 Medicare amounts; OIC/SHIBA standardized plan chart.
Plan	Most you could owe for covered care in a year	What you pay along the way	Part B excess charges	Emergency care abroad
Plan G	$283 (the Part B deductible)	Nothing	Covered	80% after $250
Plan N	$283 plus copays	Up to $20 for some office visits, up to $50 for ER visits that don't lead to admission	Not covered	80% after $250
High-deductible Plan G	Up to $2,950	You pay until the deductible is met, then nothing	Covered after the deductible	80% after $250
Plan K	Up to $8,000, plus the Part B deductible	50% of most costs until the limit	Not covered	Not covered
Plan L	Up to $4,000, plus the Part B deductible	25% of most costs until the limit	Not covered	Not covered
Plan A	$1,736 per hospital benefit period, plus $283	Part A deductible and skilled nursing coinsurance	Not covered	Not covered

Is Medigap worth the cost?

Original Medicare has no yearly limit on what you pay. Without a supplement, a hospital stay costs the Part A deductible ($1,736 per benefit period in 2026), and you pay 20% of every Part B bill with no ceiling: surgery, chemotherapy, dialysis, imaging. Medigap turns that open-ended risk into a fixed premium plus, under Plan G, one small deductible.

Whether it's worth it is a personal call, but it's not mainly about how healthy you are today. It's about whether you could absorb a large, unpredictable bill, and whether you'd want to switch later, when health questions might apply.

Common questions

Does Medigap cost more as I get older in Washington?

Not because of age. Washington requires community rating, so an insurer charges the same premium to everyone in a plan. Premiums still go up over time when the insurer gets a rate increase approved, and that increase applies to all policyholders.

Is Medigap cheaper in some Washington counties?

No. Each insurer charges the same premium everywhere it sells in the state. Counties only differ in which insurers are available.

Why doesn't this site show premiums?

Premiums change during the year and depend on discounts. We'd rather show you how to compare and give you a current quote than publish a number that could be out of date.

What's the cheapest Medigap plan in Washington?

High-deductible Plan G and Plan K generally have the lowest premiums among plans with real catastrophic protection, and Plan A is the lowest-cost plan without a deductible on Part B coinsurance. The cheapest plan isn't always the cheapest year: add up premium plus likely out-of-pocket costs.

Related guides

Medigap or Medicare Advantage: how the two paths work in WashingtonHow Original Medicare plus a Medicare Supplement differs from Medicare Advantage in structure, networks, costs and switching, with Washington's switching rules.
Your Medigap open enrollment period in WashingtonWhen your Medigap open enrollment period starts and ends in Washington, what it protects, how working past 65 changes it, and what happens if you miss it.
Turning 65 in Washington: getting Medigap right the first timeThe Medigap open enrollment window for Washington residents turning 65, what to do first, and how to compare insurers.
Guaranteed issue: when a Medigap insurer can't turn you downEvery situation where a Washington Medigap insurer must accept you without health questions, the deadlines, which plans you can buy, and the documents to keep.