Roth 401(k) Conversion Calculator

Estimate the tax on moving pre-tax 401(k) money into the plan’s Roth account, in one year or spread over several, and see whether rolling over or keeping it pre-tax leaves you more after tax when you start withdrawals. Next, open the free roth ira calculator and enter your own details to see an estimate in seconds.

Enter your in-plan Roth rollover

2026 federal tax brackets

Pre-tax 401(k) money to move to Roth

Pre-tax deferrals, employer contributions and earnings your plan lets you roll into its Roth 401(k) account.

Spread the rollover over

yrs

An equal share of what is left is rolled over at the start of each year, so less income lands in any one tax year.

Filing status

Taxable income without the rollover

Each year, after deductions.

State income tax rate

Flat rate on the taxable part. Use 0 if your state has no income tax.

Current age

yrs

Age you start withdrawals

yrs

Expected annual return

Tax rate in retirement

Federal plus state rate on pre-tax withdrawals.

More options

After-tax (non-Roth) contributions included

Money you already paid tax on. It is not taxed again; its earnings are.

Tax rate on taxable account returns

If you don’t roll over, the cash you would have paid in tax stays invested in a taxable account.

The tax is assumed to come from savings outside the plan: a direct in-plan Roth rollover has no withholding.

Your results

Total tax on the rollover

–

Roth 401(k) at withdrawal

–

Keep pre-tax, after tax

–

Ahead at withdrawal

–

Tax and timing

Taxable part of the rollover–

Federal tax / state tax–

Effective rate on the rollover–

Tax if rolled over all in 2026–

Tax due in 2026–

Break-even retirement tax rate–

Last rollover’s 5-year period ends–

First RMD you would avoid–

An in-plan Roth rollover can’t be undone. Pay the tax through extra paycheck withholding or 2026 estimated payments. Roth 401(k) accounts have had no lifetime required minimum distributions since 2024; pre-tax 401(k) money still does.

Rollover schedule

Tax each year uses the 2026 brackets and your taxable income without the rollover.

Year	Age	Rolled over	Taxable part	Federal tax	State tax	Top federal rate

Roll over or keep pre-tax: year by year

Values at the end of each year. The pre-tax column is shown after the tax you would owe on withdrawal.

Age	Roth 401(k)	Roll over: total after tax	Keep: pre-tax after tax	Keep: tax money invested	Roll over ahead by

Results are estimates for educational purposes and are not financial, tax or legal advice.