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Free online Roth IRA calculator

A Roth IRA grows tax-free — contributions are after-tax and qualified withdrawals are never taxed. This calculator projects your balance and compares it to a traditional IRA after.

About this calculator

How to use

  1. Enter your current age and retirement age.
  2. Enter your current Roth IRA balance and planned annual contribution.
  3. Set the expected annual return and your estimated tax rate at retirement.
  4. Click Calculate Roth IRA to see the tax-free Roth balance, the traditional IRA after-tax comparison, and your Roth advantage.

The formula

Both Roth and traditional balances grow the same way:

balance = (prev_balance + annual_contribution) × (1 + annual_return)

The difference is in the final comparison:

roth_value           = future_balance           (tax-free)
traditional_value    = future_balance × (1 − tax_rate)
roth_advantage       = roth_value − traditional_value

Worked example

Age 30, retiring at 65. Balance: $10,000. Contribution: $7,000/year. Return: 7%. Tax rate: 25%.

  • Roth balance at 65: approximately $1.54 million (tax-free)
  • Traditional pre-tax balance: same $1.54 million
  • Traditional after-tax (25%): approximately $1.16 million
  • Roth advantage: approximately $385,000

This gap grows with higher tax rates and longer time horizons.

Notes

  • This calculator uses the same growth model for both accounts. Real-world differences include required minimum distributions (RMDs) for traditional IRAs, state tax treatment, and estate planning implications.
  • The Roth IRA has no RMDs during the owner’s lifetime, which can allow additional tax-free compounding versus a traditional IRA.
  • Roth conversions (moving traditional IRA funds to Roth) are not modeled here.

Frequently asked

What is the 2026 Roth IRA contribution limit?
For 2026 the limit is $7,000 per year ($8,000 if you are 50 or older). Income limits also apply — eligibility phases out above certain modified adjusted gross income thresholds. Consult IRS Publication 590-A for current figures.
How does Roth compare to a traditional IRA?
Both grow the same way before taxes. The difference is when you pay tax. Roth uses after-tax money now and withdrawals are tax-free. Traditional uses pre-tax money and withdrawals are taxed as ordinary income. If you expect a higher tax rate at retirement, Roth tends to win.
What is the Roth advantage shown in this calculator?
The Roth advantage is the dollar difference between your Roth balance (fully yours, tax-free) and a traditional IRA of the same balance after applying your tax rate at withdrawal. A 25% tax rate on a $1 million traditional balance leaves $750k, so the Roth advantage is $250k.
Does Roth IRA growth count against the contribution limit?
No. Only new contributions count against the annual limit. Growth, dividends, and earnings accumulate without limit or cap.

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