Compare a Traditional, SEP or SIMPLE IRA with a Roth IRA and regular taxable savings, all measured after tax, to see which leaves you with the most.
A Traditional IRA, and its employer cousins the SEP and SIMPLE IRA, takes before-tax money. You save tax when you contribute, the money grows untaxed, and you pay ordinary income tax on what you withdraw. A Roth IRA is the mirror image: you pay tax first, then the money grows and comes out tax-free. Because both let the money grow untaxed, the real contest is between the tax rate you pay now and the one you expect to pay in retirement.
The calculator imagines you start from the same before-tax amount each year. Put it in a Traditional IRA and all of it goes to work. Put it in a Roth IRA or a taxable account and your current tax comes off first, so a smaller amount is invested. At retirement the Traditional balance is reduced by your expected retirement tax rate so the three accounts can be compared on an after-tax basis. Regular taxable savings are taxed on their growth every year at your current rate, which slows their compounding.
If your expected retirement tax rate is lower than your current rate, the Traditional IRA usually comes out ahead. If it is higher, the Roth IRA does. If the two rates match, the accounts finish equal and both beat taxable savings. The calculator does not apply contribution limits, income limits or deduction rules, so check those for your own situation.
A Traditional IRA is funded with before-tax money, so you save tax when you contribute, and you pay income tax on withdrawals in retirement. A Roth IRA is funded with after-tax money, so there is no tax saving now, but qualified withdrawals in retirement are tax-free.
It comes down to your tax rate now compared with your tax rate in retirement. If you expect a lower rate in retirement, the Traditional IRA usually wins. If you expect a higher rate, the Roth IRA usually wins. If the two rates are the same, they end up equal.
To compare fairly, the calculator assumes you start from the same before-tax amount. After paying your current tax, less is left to put into a Roth IRA or a taxable account, so those balances start smaller. The Traditional balance is shown both before tax and after the tax due on withdrawal.
No. It uses whatever contribution you enter, so it can also model SEP and SIMPLE IRAs, which allow larger contributions. Check the current IRS limit for your account type and age. For a regular IRA in 2026 it is $7,500, or $8,600 if you are 50 or older.
The growth in the taxable account is taxed every year at your current marginal rate, so only the after-tax return compounds. This is why taxable savings finish behind both kinds of IRA.
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