Retirement tax planning

Pay tax now.
Or later?

See how a Roth conversion may change what you can spend later. The comparison centers on the two numbers that matter most: today’s tax rate and your expected future tax rate.

Your conversion

THREE DETAILS
$
%
Use the rate that would apply to the conversion. Add state tax if it applies to you.
years

Planning assumptions

Adjust these if your outlook differs. If future tax rate is blank, the calculator uses today’s rate.

%
%

Assumes conversion tax is paid from cash outside the retirement account. Your entries stay in this tab and are not saved.

Compare the same dollar two ways.

One path pays income tax today and grows in a Roth. The other keeps growing tax-deferred and pays tax when withdrawn.

What this comparison includes

  • Estimated income tax on the converted amount.
  • Compounded growth at one annual return.
  • A future tax rate you can set separately.
  • The opportunity cost of using outside cash to pay the conversion tax.

What it leaves out

  • Tax brackets, deductions, credits, Medicare premiums, and Social Security taxation.
  • After-tax basis, the IRA pro-rata rule, and plan-specific restrictions.
  • Required minimum distributions and estate-planning effects.
  • Investment taxes or different returns on the cash used to pay tax.

Methodology

Future value = conversion amount × (1 + annual return)years

The Roth comparison equals future value minus the future value of the tax paid today. The traditional comparison equals future value minus estimated tax at withdrawal. That makes the projected difference mainly a comparison of tax rates—not a promise that one account type will perform better.

Last reviewed: October 2026.