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MoneyMath

401(k) Calculator — With Every Step Shown

Your 401(k) projected balance at retirement. Unlike Fidelity's black-box tool, this shows exactly how contributions, employer match, and compound growth combine year-by-year.

🟢 Updated April 2026👤 Reviewed by MoneyMath Editorial⚡ Runs in your browser · no data sent
$
Balance at Retirement (30 years)
$1,652,716
$202,196 is employer match — free money
Your total contributions$404,391
Employer match total$202,196
Growth from compounding$1,046,130
Final balance$1,652,716
Show the formula
each year: balance = balance × (1 + return) + your_contrib + match
your contrib = salary × contribution % (capped at IRS limit)
match = salary × min(contribution %, cap) × match_rate

Why we show the formula

Fidelity, Vanguard, and Schwab all have 401(k) calculators. They hide the math inside a black box, give you a final number, and push you toward their managed accounts. We show exactly what's happening year-by-year so you can verify and adjust.

The employer match is (usually) free money

If your employer offers "50% match up to 6% of salary," that means if you contribute 6% of a $80,000 salary ($4,800), they add $2,400. That's an instant 50% return on your money — better than any stock picker over any period.

Rule: always contribute AT LEAST up to the employer match cap. Not doing so is literally leaving free money on the table.

2026 contribution limits

  • Under 50: $23,500 elective contributions
  • 50+ catch-up: Additional $7,500 = $31,000 total
  • Ages 60-63 (SECURE 2.0 super catch-up): Additional $11,250 catch-up instead of $7,500 — $34,750 total. This expires at age 64.
  • Overall contribution limit (your + employer + after-tax): $70,000 (under 50), $77,500 (50+)

Traditional vs Roth 401(k)

Most employers offer both:

  • Traditional: Pre-tax contributions. Grow tax-deferred. Taxed at withdrawal.
  • Roth: After-tax contributions. Grow tax-free. Tax-free at withdrawal.

Rule of thumb: if your current tax bracket is higher than your expected bracket in retirement, go Traditional. If lower, go Roth. High-income single earners often benefit from Traditional; early-career/lower-income folks from Roth.

What to invest your 401(k) IN

Most employer 401(k) plans offer 10-30 investment options. Decision framework:

  • Beginner: Target-date fund matching your retirement year (e.g., "Vanguard Target Retirement 2055") — one-decision diversification
  • Intermediate: 80% total stock market index + 20% total bond market index — simple 2-fund portfolio
  • Advanced: 70% US total market + 20% international + 10% bonds, rebalanced annually — slight international exposure benefit

Avoid: company stock (concentration risk), high-fee managed funds (anything over 0.50% expense ratio is suspect), market timing.

What this calculator doesn't include

  • Sequence-of-returns risk (what if a 2008-style crash hits near retirement?)
  • Monte Carlo simulation (different return patterns can swing final balance by 2-3×)
  • Inflation adjustment (the nominal balance is NOT your real purchasing power)
  • Withdrawal tax (Traditional 401(k) withdrawals are taxed as ordinary income)

For full retirement planning, use Fidelity's Retirement Income Planner or Schwab's Retirement Calculator. This tool is for quick contribution-impact scenarios.

Frequently Asked Questions

Should I max my 401(k) before contributing to Roth IRA?

General rule: (1) contribute to 401(k) up to employer match, (2) max Roth IRA ($7k), (3) max HSA if available, (4) come back and max 401(k) ($23.5k), (5) taxable brokerage. The match is the first priority because it's an instant 50-100% return.

What if I leave my job with a 401(k) balance?

Four options: (1) leave it with the old employer (if allowed, usually requires $5k+ balance), (2) roll into new employer's 401(k), (3) roll into a Traditional IRA at your own broker (often better fund choices), (4) cash out (terrible — 10% penalty + income tax). Options 2 or 3 are best for most people.

What happens if I over-contribute?

The excess is returned to you as income + the growth is taxed. Your payroll system usually enforces the limit, but if you have multiple employers in one year you need to track it yourself — the limit is per person, not per employer.

Can I borrow from my 401(k)?

Most plans allow 401(k) loans up to 50% of balance or $50,000 (whichever is less). Pay yourself back with interest, typically over 5 years. Downside: if you leave the job, the loan often comes due within 60-90 days — default = income tax + 10% penalty. Treat as last resort.

Do I need to start withdrawals at 73?

Yes — Required Minimum Distributions (RMDs) begin at age 73 (raised to 75 for those born in 1960+). Roth 401(k) requires RMDs during lifetime (unlike Roth IRA which does not). Many retirees roll Roth 401(k) → Roth IRA to avoid the forced withdrawal.