IRA Calculator

Modify the values and click the Calculate button to use

Traditional After Tax: $906,391.93

Traditional (before tax): $1,066,343.45
Traditional (after tax): $906,391.93
Roth (after tax): $799,757.59
Taxable savings (after tax): $563,433.80
Tax on Traditional: $159,951.52
Total Principal: $292,500.00
Years: 35

Account comparison

Account	Balance at Retirement	After Tax
Traditional / SEP / SIMPLE IRA	$1,066,343.45	$906,391.93
Roth IRA	$799,757.59	$799,757.59
Regular taxable savings	$563,433.80	$563,433.80

Traditional balances are taxed at the retirement rate. Roth contributions are taxed now, so their after-tax balance equals the account balance. Taxable savings use an after-tax return.

What this IRA calculator does

This calculator compares three ways to save for retirement: a traditional IRA, a Roth IRA, and a regular taxable account. It projects the balance at retirement and the after-tax value of each option.

Traditional contributions are assumed to be made before tax and taxed at withdrawal. Roth contributions are assumed to be made after tax and grow tax-free. The taxable account pays tax on its returns each year.

How to use this calculator

Enter the current balance and annual contribution.
Enter the expected annual return.
Enter your current age and retirement age.
Enter your current marginal tax rate and expected retirement tax rate.
Click Calculate.

The default example starts at age 30 with $30,000, contributes $7,500 per year, earns 6%, and retires at 65. The current tax rate is 25% and the retirement tax rate is 15%.

IRA comparison formulas

For a traditional IRA:

Balance = P × (1 + r)^n + C × ((1 + r)^n − 1) / r
After-tax balance = Balance × (1 − retirement tax rate)

For a Roth IRA, contributions are reduced by the current tax rate before they are invested:

Roth balance = (P + C × annuity factor) × (1 − current tax rate)

The taxable account grows at an after-tax return:

After-tax return = r × (1 − current tax rate)

P is the current balance, C is the annual contribution, r is the annual return, and n is the number of years until retirement.

What the results include

Traditional before tax: the account balance at retirement.
Traditional after tax: the balance after retirement tax.
Roth after tax: the tax-free Roth balance.
Taxable savings after tax: the taxable account balance.
Tax on traditional: the difference between the before-tax and after-tax balance.
Total principal: current balance plus all contributions.

Assumptions and limitations

The calculator assumes annual contributions at the end of each year and a constant return and tax rate. It does not model contribution limits, catch-up contributions, required minimum distributions, state taxes, penalties, or changes in tax law. The taxable account assumes tax is paid on returns each year at the current marginal rate.

Frequently asked questions

What is the difference between a traditional and Roth IRA?

Traditional contributions may be deductible now, and withdrawals are taxed later. Roth contributions are made with after-tax dollars, and qualified withdrawals are tax-free.

Why can the traditional balance be higher before tax but lower after tax?

Traditional contributions are not reduced by current tax, so more money is invested. The entire balance is taxed at withdrawal. Roth contributions are smaller, but the growth is not taxed.

Does this include IRA contribution limits?

No. The calculator uses the contribution amount you enter. Annual IRS limits and eligibility rules are not applied.

What about required minimum distributions?

RMDs are not modeled. They can change the after-tax value of a traditional IRA and the timing of withdrawals.

Source

References:

Disclaimer

This calculator is for informational and educational purposes only. It is not tax or investment advice. Consult a tax professional about your situation.

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