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Roth Conversion Calculator

Compare keeping a traditional IRA or 401(k) versus converting to Roth: pay tax now for tax-free growth or defer tax until retirement.

Roth conversion comparison

Higher modeled value

Traditional account

The traditional account is higher by $7,739 after taxes at retirement in this model.

Break-even retirement tax rate: 24.00%

Path A: Keep traditional

Future value (pre-tax)
$386,968
After-tax in retirement
$301,835

Path B: Convert to Roth

Tax owed at conversion
$24,000
Roth starting balance
$100,000
Outside funds' future value
$92,872
Net value at retirement
$294,096

Before you convert, consider

  • Roth IRAs are not subject to required minimum distributions (RMDs) during the original owner's lifetime, while traditional IRAs are.
  • A large Roth conversion can push you into a higher tax bracket and trigger IRMAA Medicare premium surcharges in retirement.
  • Roth balances pass to heirs income tax free, which can make conversions attractive for estate planning.
  • Paying conversion tax from outside the IRA preserves more money inside the Roth, but those outside funds also give up future investment growth.
  • Each conversion has a separate five-year clock for avoiding the 10% additional tax on converted principal withdrawn before age 59 1/2. Qualified earnings use a different five-year clock that starts with your first Roth IRA contribution and also requires a qualifying event.

Estimate only. Assumes outside funds would earn the same annual return and ignores taxes on that investment growth, state tax rules, and changes in tax law. Consult a tax advisor before converting.

Roth Conversion Tax Examples

Tax due when converting a $50,000 amount at selected entered marginal rates.

Conversion AmountEntered Tax RateTax Paid From Outside FundsAmount Converted
$50,000.0010%$5,000.00$50,000.00
$50,000.0012%$6,000.00$50,000.00
$50,000.0022%$11,000.00$50,000.00
$50,000.0032%$16,000.00$50,000.00
$50,000.0037%$18,500.00$50,000.00

The calculator compares the tax treatment under your entered current and retirement tax assumptions.

Frequently Asked Questions about the Roth Conversion Calculator

How does this Roth conversion calculator work?
It compares two paths over your time horizon. Path A keeps the money in a traditional IRA or 401(k), grows it tax-deferred, and applies your expected retirement tax rate. Path B pays income tax on the converted amount today at your current marginal rate, then grows the after-tax balance tax-free in a Roth.
When does a Roth conversion usually make sense?
Conversions tend to win when your tax rate in retirement will be higher than today, when you have many years until withdrawals so tax-free growth compounds, and when you can pay the conversion tax with funds from outside the retirement account.
Why does paying the conversion tax from outside funds matter so much?
If you pay the tax out of the conversion itself, you shrink the Roth starting balance and lose decades of tax-free compounding on that amount. Converting $100,000 at 24% leaves only $76,000 in the Roth, which grows to about $294,096 at 7% over 20 years. Paying tax from outside keeps the full $100,000 working, which grows to about $386,968.
What is the break-even retirement tax rate?
It is the retirement marginal rate at which the after-tax outcomes of the two paths are equal. Under the simplified comparison, that rate equals your current marginal rate. If you expect to be taxed above it in retirement, conversion wins; below it, keeping traditional wins.
What does this calculator not account for?
It does not model future tax law changes, the pro-rata rule for IRAs with mixed pre-tax and after-tax money, IRMAA Medicare surcharges, or state estate rules. Each conversion has its own five-year clock for the 10% additional tax on converted principal, while the qualified-earnings clock starts with your first Roth IRA contribution and also requires a qualifying event. Run scenarios with a tax advisor for large conversions.

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