Retirement & Investing

401k Calculator

Project your 401k balance growth over time.

Enter your current 401k balance, your monthly contribution (including any employer match you receive), your expected annual return, and years until retirement to project your future balance.

Enter a valid return rate.
Enter a valid number of years.

Projected Future Value

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Total Contributed

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Investment Growth

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How to Use This Tool

  1. Enter your current savings balance (enter 0 if starting fresh).
  2. Enter how much you plan to contribute each month.
  3. Enter your expected annual return and the number of years until you'll need the money.
  4. Click Calculate Future Value to see your projected balance, total contributions, and investment growth.

The Future Value Formula

This calculator projects growth using compound interest applied monthly, combining both your existing balance and ongoing contributions:

Future Value = Current Balance × (1 + r)ⁿ + Monthly Contribution × [((1 + r)ⁿ − 1) ÷ r]

Where r is the monthly return rate (annual rate ÷ 12) and n is the total number of months.

Don't Forget Your Employer Match

If your employer offers a matching contribution, include the combined amount (your contribution + employer match) in the "Monthly Contribution" field for an accurate projection — employer matching is essentially free money that can dramatically boost your long-term balance.

2024 Contribution Limits

For reference, the IRS 401(k) employee contribution limit for 2024 was $23,000 (or $30,500 for those 50+), though these limits are adjusted periodically — check current IRS guidance for the applicable year's limit.

Why Starting Early Matters So Much

Because returns compound on both your contributions and your prior growth, money invested earlier has dramatically more time to compound. Two savers contributing the same monthly amount, but starting 10 years apart, can end up with a significantly different final balance — the earlier starter often ends up with a much larger sum despite contributing the same total amount over their overlapping years.

Important Caveat

This projection assumes a constant annual return, which real investments never provide exactly — actual markets fluctuate year to year. Use a conservative estimated return (historically, diversified stock market returns have averaged around 7-10% annually before inflation over long periods, though individual results vary) and treat this as a planning estimate, not a guarantee.

Frequently Asked Questions

What rate of return should I use?

This depends on your investment mix and risk tolerance. Many long-term planning tools use a conservative estimate (e.g., 6-8% for diversified stock-heavy portfolios), but actual returns vary year to year and are never guaranteed.

Does this account for inflation?

No, this shows nominal (non-inflation-adjusted) future value. To estimate purchasing power in today's dollars, you would need to reduce the growth rate by your assumed inflation rate.

Does this account for taxes or fees?

No, this is a simplified gross growth projection. Taxes (depending on account type) and investment fees would reduce your actual real-world balance below this projection.

This calculator is provided for general informational and estimation purposes only. Results should not be treated as professional financial, tax, legal, medical, or engineering advice. Always verify critical calculations with a qualified professional or official source before making decisions.