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401(k) Calculator

Calculate how much your 401(k) will grow by retirement. Enter your contribution, employer match, and expected return to project your nest egg and monthly retirement income.

US estimateLast reviewed 15 August 2026Reviewed after a methodology changeSource: IRS — 401(k) contribution limits

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% of salary

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Rates & sources2026

Employee 401(k) elective deferral limit for 2026. Catch-up and employer match are not assumed unless you enter them.

Rates used for 2026
Band / figureRate
Employee deferral limit$24,500
Age 50 catch-up (separate)not auto-applied

Source: IRS — 401(k) contribution limits — source checked for 2026.

When to use this calculator

  • Before choosing between saving, investing or changing a contribution.
  • When you want to compare cautious, base and optimistic return assumptions.
  • When you need a projection before making a longer-term decision.
  • When you want to see whether starting earlier or contributing more changes the outcome more.

A realistic US planning example

Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.

A realistic US planning example
InputValue
Your Current Age35
Retirement Age35
Current 401(k) Balance ($)$1,400
Your Annual Contribution ($)$250 per month

After entering these figures, review projected balance, your contributions and investment growth together rather than in isolation. Then rerun the tool with one input adjusted.

How to read your results

Projected Balance

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Your Contributions

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Investment Growth

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Employer Match/yr

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

4% Rule Monthly Income

The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.

Method & assumptionsAuthoritative sources

This calculator projects your 401(k) balance at retirement using annual compounding, applying your contribution and estimated employer match each year to a growing balance. Employee contributions are capped at the 2026 IRS limit of $24,500; employer matching is calculated as a percentage of eligible salary up to the cap you specify. The expected return is applied once per year on the sum of the opening balance and that year's total contributions. Results assume contributions remain constant in nominal dollars and do not account for future IRS limit increases, salary growth, or inflation. The 4% monthly income figure is derived from the projected balance using the widely cited Bengen safe withdrawal guideline and is illustrative only.

This tool is intended for educational planning purposes under US rules and should not be treated as personalised investment advice. Actual growth will vary based on market performance, fund fees (expense ratios), and plan-specific rules. The IRS periodically adjusts contribution limits for cost-of-living, so always verify current limits at IRS.gov before making contribution decisions. Consult a fee-only financial advisor or Certified Financial Planner (CFP) to build a full retirement income strategy.

Common mistakes

  • !Using an assumption that is not supported by a current local quote, bill, statement or official source.
  • !Treating a generic estimate as a lender, provider, payroll or tax authority decision.
  • !Mixing monthly and annual inputs without converting them consistently.
  • !Testing only one scenario instead of checking how a cautious assumption changes the result.

What to do next

  • Run a second scenario with a cautious assumption so you can see the downside clearly.
  • Compare the result with the related calculators below before making a decision.
  • Check current local rules, eligibility and provider terms before applying or committing money.
  • Keep a record of the assumptions so you can update the estimate when a quote, bill or pay figure changes.

Frequently asked

The calculator applies compound annual growth to your starting balance plus yearly contributions — both yours and your employer's match — over the number of years until retirement. It caps employee contributions at the 2026 IRS limit of $24,500 and estimates employer matching based on the percentage and salary cap you enter. The projected balance then feeds a 4% withdrawal rule to estimate sustainable monthly income.

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