Roth IRA Growth Calculator Formula

Understand the math behind the roth ira growth calculator. Each variable explained with a worked example.

Use the Roth IRA Growth Calculator

Formulas Used

Future Value (Tax-Free)

future_value = monthly_rate > 0 ? current_balance * pow(1 + monthly_rate, num_months) + monthly_contrib * (pow(1 + monthly_rate, num_months) - 1) / monthly_rate : current_balance + monthly_contrib * num_months

Total Contributions

total_contributions = current_balance + annual_contribution * years

Tax-Free Growth

tax_free_growth = (monthly_rate > 0 ? current_balance * pow(1 + monthly_rate, num_months) + monthly_contrib * (pow(1 + monthly_rate, num_months) - 1) / monthly_rate : current_balance + monthly_contrib * num_months) - current_balance - annual_contribution * years

Variables

VariableDescriptionDefault
current_balanceCurrent Roth IRA Balance(USD)15000
annual_contributionAnnual Contribution(USD)7000
annual_returnExpected Annual Return(%)7
yearsYears to Grow(years)30
monthly_rateDerived value= annual_return / 12 / 100calculated
monthly_contribDerived value= annual_contribution / 12calculated
num_monthsDerived value= years * 12calculated

How It Works

Roth IRA Growth

Roth IRA contributions are made with after-tax dollars, but all growth and qualified withdrawals are completely tax-free.

2024 Contribution Limits

AgeLimit Under 50$7,000 50 and over$8,000

Key Advantage

Unlike Traditional IRAs and 401(k)s, Roth IRAs have no Required Minimum Distributions (RMDs), so your money can grow tax-free for as long as you want.

Worked Example

$15,000 balance, $7,000/year contributions, 7% return, 30 years.

current_balance = 15000annual_contribution = 7000annual_return = 7years = 30
  1. 01Monthly contribution = $583
  2. 02Current balance grows: $15,000 to ~$114,200
  3. 03Contributions grow to ~$708,800
  4. 04Total = ~$823,000 (all tax-free)
  5. 05Total contributed = $15,000 + $210,000 = $225,000
  6. 06Tax-free growth = ~$598,000

Frequently Asked Questions

What is a Roth IRA?

A Roth IRA is a retirement account funded with after-tax money. Qualified withdrawals after age 59.5 (and 5 years of account ownership) are completely tax-free.

Who can contribute to a Roth IRA?

Single filers with MAGI under $161,000 and married filers under $240,000 can contribute the full amount (2024 limits). Backdoor Roth conversions may be available for higher earners.

Roth IRA vs Traditional IRA?

Roth: pay taxes now, withdraw tax-free. Traditional: deduct now, pay taxes on withdrawals. Choose Roth if you expect higher future tax rates.

Ready to run the numbers?

Open Roth IRA Growth Calculator