Roth conversion calculator V2 · simple view
Pay the bills.
Find your Roth window.
See what you could convert after covering living costs, what it could cost today, and how it might change future taxes.
A ballpark illustration. Federal income tax only.
Your starting point
Rough numbers are enough.
Start with today’s balances. For a couple, use one combined spending budget and count shared money once.
Cash is now separate. If your saved brokerage/savings total includes cash, move that portion into “Cash / savings today” so it is counted once.
Your Roth conversion window
How much could you convert to Roth after covering living costs?
First cover living costs and their tax. Green shows the estimated Roth conversion amount within your total tax-cost limit.
Your saved percentage now limits the total added tax cost, including effects on stock gains and Social Security. Your balances and other inputs are unchanged.
Move over the graph or tap a year. Green stays invested in Roth; it does not pay living costs.
The future tradeoff
Your federal income tax each year.
Estimated yearly tax bill ($) · includes tax on stock gains
Move over the graph or tap a year to update the spending and conversion breakdown below.
Show the work for this year
The longer view
Total taxes across these years
Adds this year through the chart’s last year, including conversion costs. Dollars are not discounted. This is a tax comparison, not a measure of total wealth or a promise of savings.
The few assumptions behind the picture
Simple inputs, careful tax math.
Your chosen percentage limits the estimated added federal income tax divided by the amount converted. It includes extra tax on stock gains, Social Security and sales needed to pay conversion tax. It is an average cost for the conversion; the last dollars may fall in a higher marginal bracket. The existing tax bill is paid first and is excluded from this percentage.
We fund living costs and federal income taxes before allowing a conversion. Conversion money stays in Roth; it never pays the bills. Income-tax deductions and taxable Social Security are estimated automatically.
Cash savings is a separate balance: withdrawing it creates no new income tax. We spend cash before selling investments, after any traditional withdrawals chosen for living costs. For every stock sale, we treat 50% as long-term taxable gain and 50% as money already invested. That split stays the same every year, regardless of growth; 50% is not the tax rate. Other income is assumed fully taxable, including rent after property costs.
One growth rate applies to traditional, Roth, and invested brokerage money. Cash savings has no assumed growth; include any expected cash interest in other income. Living costs, other income, benefit amounts and 2026 tax bands stay flat. We do not add automatic inflation, raises or rental appreciation. These are example assumptions, not market forecasts.
What this picture leaves out.
Roth stays invested. If income and your chosen spending accounts cannot cover the bills, we flag a funding gap; we do not silently spend Roth. Unused income and excess RMDs are not reinvested. No future contributions are added.
Age 60 is our whole-year shortcut for 59½ access to traditional accounts. No early-access exceptions or penalties are modeled. Social Security starts at age 67 for each person, using the monthly benefit you enter.
No state tax, Medicare/ACA changes, NIIT, AMT, self-employment tax, or survivor simulation. A surviving spouse may face narrower single-filer brackets; that can strengthen the case for Roth, but it is not included in these lines.
An educational guesstimation tool, not individualized financial or tax advice. Use it to frame a conversation with an advisor.
IRS sources: 2026 tax bands · Capital gains · Interest · Social Security · RMDs and distributions
Same question. A simpler starting point. The original calculator is still here.