The $172K Healthcare Cost Your Retirement Calculator Ignores

You did everything right. Maxed your 401(k). Ran Monte Carlo simulations. Got an 85% success rate. Then you retired, and healthcare costs ate through your projections like termites through a wooden floor.

Here's the problem: your retirement calculator almost certainly uses a single inflation number -- usually 2.5% to 3% -- for everything. Groceries, housing, travel, and healthcare all get the same flat rate. That assumption is catastrophically wrong for healthcare.

The Numbers That Should Worry You

Medicare Part B premiums jumped from $185 to $202.90 per month in 2026 -- a 9.7% increase in a single year. General CPI for the same period? About 3.3%.

This isn't an anomaly. Over the past 20 years, medical costs have consistently inflated at roughly 5-7% annually -- about double the general CPI rate. Fidelity's 2025 Retiree Health Care Cost Estimate puts the lifetime healthcare cost for a 65-year-old at $172,500 in after-tax savings. And that number assumes you're healthy.

Let's make this concrete.

The 30-Year Math Nobody Shows You

Say you're 55, planning to retire at 60, expecting to need $6,000/year for healthcare initially (premiums plus out-of-pocket). Most calculators inflate that at 3%.

That's nearly $190,000 in underestimated healthcare spending over 30 years. From one wrong assumption.

At year 20, your calculator says you need $10,829 for healthcare. Reality demands $19,234. That's 78% more than projected -- every single year, compounding against you.

IRMAA Makes It Worse

If your Modified Adjusted Gross Income crosses certain thresholds, you pay income-related monthly adjustment amounts (IRMAA) on top of standard Medicare premiums. In 2026, the surcharges look like this:

A Roth conversion that pushes your MAGI from $105,000 to $134,000 costs you an extra $102/month in Part B premiums alone -- $1,224/year you didn't plan for. And IRMAA uses a 2-year lookback, so the damage hits you well after the conversion.

This interacts with medical inflation in a vicious way. As healthcare costs rise faster than general inflation, the real purchasing power of each IRMAA tier shrinks. More retirees get pushed into higher tiers over time without any real increase in income.

Why Your Calculator Gets This Wrong

Most retirement calculators -- even good ones -- model inflation as a single number. Every expense category gets the same 2.5% or 3% annual increase. This works reasonably well for groceries and utilities. It fails completely for three categories:

1. Healthcare (~5-7%/year historically) -- the biggest gap
2. Education (~5%/year) -- relevant if you're funding grandchildren's college
3. Housing in hot markets (~3.5-4%/year) -- relevant for renters in HCOL areas

The problem compounds. After 20 years of retirement, a 3-percentage-point inflation differential means your healthcare projection is off by nearly 80%. After 30 years, it's off by over 130%.

How to Actually Model This

The right approach uses per-category inflation rates that reflect economic reality:

• General expenses: 2.5-3% (tied to CPI)
• Healthcare/Medicare: 5-7% (tied to medical CPI, with separate IRMAA threshold tracking)
• Education: 5% (if applicable)
• Housing: 3.5% (if renting in growth markets)
• Fixed payments: 0% (mortgage, fixed annuities)

Even better, model inflation stochastically -- as a random variable, not a fixed assumption. Real inflation comes in waves. The 1970s saw healthcare inflation spike above 10%. A fixed 5% assumption might be reasonable on average but misses the possibility of a bad decade hitting right when you're depleting your portfolio.

QuantCalc's Monte Carlo simulator now models inflation per-category, with stochastic AR(1) mean-reversion and regime-switching options. You can set healthcare costs to inflate at their historical rate while keeping general expenses at CPI. The result: more realistic projections that don't silently assume your $6,000/year health premium stays manageable forever.

Run your own scenario with per-category inflation modeling at quantcalc.app

What to Do About It

Three concrete steps:

1. Separate your healthcare budget from general expenses. Model it with a 5-6% inflation rate, not 3%. If your calculator doesn't allow per-category rates, add a separate healthcare line item and manually inflate it higher.

1. Plan Roth conversions around IRMAA thresholds. Convert early (before 63) when your MAGI is low, to avoid 2-year-lookback IRMAA surcharges during peak Medicare years. Our tax-efficient withdrawal strategies guide covers the sequencing in detail.

1. Stress-test your plan with medical inflation shocks. What happens if healthcare costs rise 8% for five consecutive years? The ACA premium tax credit repayment trap shows how quickly ACA subsidies evaporate when income projections miss by even small amounts.

The $172,500 Fidelity number is scary enough. The gap between flat-CPI projections and reality-adjusted healthcare costs is scarier. Don't let a bad inflation assumption be the thing that wrecks an otherwise solid retirement plan.

Frequently Asked Questions

How much should I budget for healthcare costs in retirement?

Fidelity estimates $172,500 in after-tax savings for a single 65-year-old retiree. Couples should plan for $315,000 or more. These figures assume Medicare enrollment at 65 -- if you retire before Medicare eligibility, add $15,000-$25,000 per year for ACA marketplace coverage or COBRA.

Why does medical inflation run higher than regular CPI?

Three structural factors drive medical costs faster than general inflation: prescription drug development costs, an aging population increasing demand for services, and administrative overhead in US healthcare that has no equivalent in other categories. The BLS Medical Care CPI component has averaged 5-7% annually over the past 20 years versus 2.5-3% for headline CPI.

Can I reduce IRMAA surcharges on Medicare premiums?

Yes. The most effective strategy is managing your MAGI in the two years before you turn 65, since IRMAA uses a 2-year lookback. Complete Roth conversions before age 63, minimize capital gains realizations near the thresholds, and consider qualified charitable distributions (QCDs) after 70.5 to reduce taxable RMD income.

What retirement calculator models healthcare inflation separately?

QuantCalc lets you set per-category inflation rates for healthcare, education, housing, and general expenses -- plus stochastic inflation models that capture the randomness of real-world cost increases. Most free calculators use a single flat inflation rate for all expenses.

QuantCalc is an independent educational tool. Not affiliated with, endorsed by, or sponsored by any referenced firm including BlackRock, J.P. Morgan, Vanguard, GMO, Schwab, Invesco, Morningstar, or Fidelity. Return assumptions derived from publicly available research. All trademarks belong to their respective owners. Not financial advice.