401(k) Calculator

A 401(k) is the most common workplace retirement account in the United States. It lets you contribute pre-tax (or post-tax for Roth 401(k)) money straight from your paycheck into investments that grow tax-deferred until you withdraw in retirement. Most employers add a contribution of their own — the employer match — which is essentially a guaranteed return you cannot replicate anywhere else.

This calculator projects your retirement balance based on your contribution rate, employer match, expected investment return, and time horizon. The hardest lever to overcome is time — every year of contributions matters more than the last because of compounding. If you're reading this in your 20s or 30s, even small consistent contributions compound into life-changing balances.

Age 30, retiring at 65 (35-year horizon). Salary $75,000, contributing 10%, employer matches 50% up to 6%, current balance $25,000, 7% annual return:

• Your contribution: $7,500/year
• Employer match: $2,250/year
• Total annual: $9,750
• Projected balance at 65: ~$1.5 million
• Of that, your contributions = $262,500, employer match = $78,750, growth ≈ $1,160,000

Investment growth dwarfs the contributions over a 35-year horizon. That's compounding doing the work — and it's why missing the early years is so costly.

• Onboarding at a new job — figuring out the contribution rate that captures the full match.
• Annual benefits enrollment — running "what if I bumped my contribution by 1%?" scenarios.
• Retirement planning — projecting whether you're on track for the lifestyle you want.
• Considering a career change — comparing job offers including the value of differing 401(k) matches.
• Catch-up planning — for those 50+, modeling how catch-up contributions accelerate the balance.

• Skipping the employer match. Even 1% under the match limit leaves money on the table — usually thousands per year.
• Cashing out when changing jobs. Taxes plus a 10% penalty plus lost compounding can turn a $20k balance into $80k of regret over a career.
• Investing too conservatively young. 30-year horizons handle stock-market volatility well. Holding mostly cash or bonds in your 20s usually underperforms badly.
• Ignoring fees. A 1% expense ratio sounds tiny but compounds into ~25% less wealth over 30 years. Look for low-fee index funds in your plan.
• Forgetting Roth IRA. Once you hit your match, a Roth IRA can be a smart next step for tax diversification.