401k Calculator
Estimate your 401k balance at retirement based on your current balance, salary, contribution rate, employer match, and expected returns.
A 401(k) is an employer-sponsored retirement savings plan in the United States that allows employees to invest pre-tax (or Roth after-tax) dollars. The combination of tax advantages and employer matching makes it one of the most powerful wealth-building tools available.
Future Value with regular contributions:
FV = PMT × [((1 + r)ⁿ − 1) / r] + PV × (1 + r)ⁿ
What each variable means:
- PMT — your monthly contribution (employee portion)
- r — monthly return rate (annual rate ÷ 12)
- n — total number of months until retirement
- PV — current 401(k) balance (present value)
- Employer Match — free money added by your employer, typically 50–100% of your contribution up to a salary limit
2024 contribution limits:
- Employee max: $23,000/year ($1,916.67/month)
- Catch-up (age 50+): additional $7,500/year
- Total combined (employee + employer): $69,000/year
Worked example: Age 30, current balance $15,000, contributing $500/month. Employer matches 50% up to 6% of $70,000 salary = $2,100/year ($175/month). Total monthly investment = $675. Assumed return: 7%/year. Retire at 67 (37 years = 444 months).
r = 7% / 12 = 0.5833% FV from contributions = $675 × [((1.005833)⁴⁴⁴ − 1) / 0.005833] = $675 × [(13.05 − 1) / 0.005833] = $675 × 2,066 = $1,394,550 FV from existing $15,000 = $15,000 × (1.005833)⁴⁴⁴ = $15,000 × 13.05 = $195,750 Total projected balance: ~$1,590,300
Total out-of-pocket contributed: $500 × 444 = $222,000 Employer gave you: $175 × 444 = $77,700 Investment growth: ~$1,290,600
Key rule: Always contribute at least enough to capture the full employer match — it is an immediate 50–100% return on that portion of your money.
Traditional vs Roth: Traditional 401(k) reduces taxable income now but withdrawals are taxed. Roth 401(k) uses after-tax dollars but grows and is withdrawn completely tax-free.