When is the best age to start Roth conversions?

Most retirees benefit most from converting between retirement and RMD age (typically 60 to 73). That gap is your bracket-arbitrage window: ordinary income drops, but RMDs haven't started yet, so you can fill the 22% or 24% bracket cheaply. Once RMDs kick in, your bracket is already partially filled before you convert a single dollar.

How much should I convert per year?

It depends on (1) the top of your target bracket, (2) the IRMAA tier you want to stay under, and (3) how much outside money you have to pay the tax. A typical 'bracket-fill to 22% top' ladder converts $100K to $300K per year for high-balance retirees. Our calculator runs the exact math for your numbers.

Can a Roth conversion push me into a higher tax bracket?

Yes, and that's often a feature, not a bug. If your current bracket is lower than the bracket your RMDs will force you into starting at age 73 (or that your surviving spouse will face at single rates), paying 24% now beats paying 32%+ later. The calculator shows your bracket trajectory year by year.

Does a Roth conversion affect my Medicare premiums?

Yes, Roth conversions count as MAGI for IRMAA purposes, with a 2-year lookback. A conversion in 2026 affects your 2028 Medicare Part B and D premiums. The calculator models this lag and includes IRMAA in the lifetime tax cost.

Is there a deadline to do a Roth conversion?

Roth conversions must be completed by December 31 of the tax year. They cannot be done retroactively in April like an IRA contribution. The 5-year rule on each conversion's earnings also starts January 1 of that year.

Why does doing nothing cost my family so much?

Three compounding losses: (1) RMDs at 73 force you into higher brackets just as your spouse may die, pushing the survivor into single rates with the 'widow's penalty,' (2) every dollar in a Traditional IRA at death gets fully taxed by your heirs over 10 years under SECURE Act rules, often at their peak earning bracket, and (3) high RMDs spike IRMAA every year for the rest of your Medicare years.

Roth Conversion Calculator: What Doing Nothing Costs

Step 1

You and your accounts today

A few numbers to seed the simulation. The defaults reflect a typical Southern California household. Change them to yours.

Filing Status

Your Age

Life Expectancy (plan-to age) SSA average: 87 male / 90 female at age 65. Plan past average to be safe.

State

Traditional IRA / 401(k) Balance

Existing Roth Balance

Outside (Taxable) Savings, used to pay conversion tax If $0, taxes will be paid from the IRA itself (less efficient).

Expected Investment Return (annual)

Inflation / COLA (annual)

Step 2

Your income picture through retirement

All amounts in today's dollars. The simulator inflates them automatically each year.

Other Ordinary Income (pension, wages, rental)

Pension/Wages Stop at Age After this age, only Social Security + RMDs + portfolio.

Interest, Dividends, Capital Gains (annual)

Your Social Security at FRA (annual) Annual benefit at your full retirement age (~67).

Spouse's Social Security at FRA (annual)

SS Claiming Age

Step 3

Your conversion strategy

The optimizer compares doing nothing against a multi-year conversion ladder using your chosen ceiling.

Conversion Strategy

Custom Conversion / Year (if custom)

Convert From Age

Convert Through Age Default: stop before RMDs begin (age 73 if born 1951 to 1959, age 75 if born 1960+).

Heir's Marginal Tax Rate (for estate value) Traditional IRA passed at death is taxed at the heir's bracket on withdrawal. Roth is tax-free.

Want this walked through with you?

This tool runs the math. Hans walks through how the publicly available IRS bracket, RMD, and Medicare IRMAA rules apply to your specific numbers. Pure math education, not financial advice. No products sold.

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Hans Goldstein

Founder & Executive Director · Retirement Literacy Foundation, a 501(c)(3) non-profit

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Roth Conversion Calculator:
What Does "Doing Nothing" Cost?

You and your accounts today

Your income picture through retirement

Your conversion strategy

Want a clean PDF + a walkthrough?

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What Happens Next

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Hans Goldstein

Free live workshop: Social Security & Taxes