Medicare Calculators & Tools
Fifteen free calculators covering eligibility, costs, IRMAA, plan comparisons, enrollment timing, savings programs, and what to do about coverage before you're even eligible — built on official CMS and Medicare.gov data.
Medicare has more moving parts than any other program on this site — four separate "parts," a handful of enrollment windows with real financial penalties for missing them, and a private-plan market layered on top of the public program. Most of the confusion people run into comes down to three questions: am I enrolled correctly and on time, what will this actually cost me, and which coverage path — Original Medicare plus Medigap, or Medicare Advantage — fits my situation.
Am I Eligible, and Am I Enrolling on Time?
Most people become eligible at 65, but eligibility and enrollment timing are two different things. Missing your Initial Enrollment Period (the seven-month window around your 65th birthday) can mean a late enrollment penalty that's added to your premium permanently — not a one-time fee. If you're still working with employer coverage, you may be able to delay without penalty, but the rules depend on your employer's size and plan type. Start with the Medicare Eligibility Checker and the Enrollment Period Finder to confirm your specific windows, and use the Late Enrollment Penalty Calculator if you think you may have already missed one. If you're already on Medicare and just want to know how many days are left to switch plans this year, the AEP Countdown tracks it live.
Original Medicare vs. Medicare Advantage vs. Medigap
Original Medicare (Parts A and B) is federally administered and accepted by any provider that takes Medicare nationwide, but it leaves real gaps — no annual out-of-pocket cap, 20% coinsurance on most Part B services, and no routine dental, vision, or hearing coverage. People typically fill those gaps one of two ways: a private Medigap (Medicare Supplement) policy alongside Original Medicare, or switching to a Medicare Advantage (Part C) plan, which bundles in extra benefits and usually drug coverage but works through a network. The two paths aren't compatible with each other. Our Medicare Advantage vs Original Medicare comparison and Medigap Plan Comparison Tool lay out the actual trade-offs side by side.
What Will This Actually Cost?
Premiums, deductibles, and coinsurance change every year, and higher earners pay more through IRMAA — a surcharge on Part B and Part D added based on income from two years prior, and it applies as a cliff rather than a gradual increase. The Medicare Cost Calculator and IRMAA Calculator use current official figures to show your actual expected premium. If you take multiple prescriptions, the Part D Coverage Gap Calculator shows where you land relative to the coverage gap and catastrophic threshold for the year. If you're weighing a Roth conversion, the Roth Conversion IRMAA Planner shows whether it would push you into a higher bracket before you commit to an amount.
Help If Money Is Tight
Medicare has built-in programs for beneficiaries with limited income and resources that many people never apply for simply because they don't know they exist. Medicare Savings Programs (QMB, SLMB, and QI) can cover Part B premiums and sometimes cost-sharing; Extra Help (the Low-Income Subsidy) reduces Part D drug costs significantly. Check both with the Medicare Savings Program Eligibility Calculator and the Extra Help Eligibility Calculator. If you also qualify for Medicaid, the PACE Program Eligibility Checker and our Prescription Savings Finder cover further layers of assistance.
Not Yet on Medicare? The Coverage Gap Before 65
If you retire, or lose employer coverage, before turning 65, you still need health insurance in the meantime — and that's a completely different system, not an early version of Medicare. The ACA Subsidy Calculator estimates your 2026 Marketplace premium tax credit for that gap, including the subsidy cliff that came back this year after several years of enhanced, uncapped subsidies. It's worth understanding before you decide when to retire or claim Social Security, since your income in those years directly affects how much help you get.
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What's the difference between Original Medicare and Medicare Advantage?
Original Medicare (Part A and Part B) is run directly by the federal government and lets you see any provider that accepts Medicare nationwide. Medicare Advantage (Part C) is a private-plan alternative that usually bundles in Part D drug coverage and extra benefits, but typically uses a network and requires referrals.
What happens if I miss my Initial Enrollment Period?
You may owe a late enrollment penalty added permanently to your Part B and/or Part D premium, and you may have to wait for the next General Enrollment Period to sign up — unless you qualify for a Special Enrollment Period, most commonly because you had coverage through an employer.
Do I need a Medigap plan if I have Original Medicare?
Not required, but Original Medicare alone leaves you responsible for deductibles, coinsurance, and 20% of most Part B costs with no annual cap. A Medigap policy covers some or most of that gap. It cannot be paired with Medicare Advantage.
What is IRMAA and who has to pay it?
IRMAA (Income-Related Monthly Adjustment Amount) is a surcharge added to Part B and Part D premiums for higher-income beneficiaries, based on your tax return from two years prior. Most beneficiaries never hit the income threshold and pay the standard premium.
This page is for general educational purposes and is not affiliated with Medicare.gov or CMS. All figures used in our calculators come directly from official CMS publications — see our Data Sources page for details.