401(k) contribution calculator

How this calculator works

This calculator projects 401(k) balance growth from employee contributions, employer match, investment returns, and optional salary increases over years until retirement. Enter annual salary, your contribution percentage, employer match rate and cap, current balance, years to retirement, expected annual return, and annual salary increase.

Each simulated month adds employee and employer contributions based on current salary, then applies monthly investment return. Salary increases once per year at the rate you enter, which raises future contribution dollar amounts because they are percentages of pay.

Outputs include projected balance, monthly employee and employer contributions at current salary, whether you capture the full match, and suggested contribution percentage to maximize match. Capturing full match means contributing at least enough to receive the maximum employer contribution—for example, 3% of salary when the employer matches 100% up to 3%.

The projection is pretax planning math. It does not model IRS contribution limits, catch-up contributions, vesting schedules, plan fees, Roth vs. traditional treatment, or withdrawal taxes.

What affects the result

Several levers compound over decades.

• Contribution percentage directly sets how much you save each month. Increasing from 4% to 6% when match cap is 3% adds employee savings without increasing employer match beyond the cap.
• Employer match rate and cap determine free money. Missing match by contributing below the cap leaves compensation on the table—often described as an immediate return you forfeit.
• Current balance provides a head start; growth applies to existing assets plus new contributions.
• Years to retirement extends compounding time. More years magnify the gap between contribution rates.
• Expected annual return affects ending balance significantly over long horizons but is uncertain. Test 5%, 6%, and 7% scenarios.
• Annual salary increase raises contribution dollars over time when contributions are salary percentages.

Employer match captured at Yes with a 100% match up to 3% means you contribute at least 3% of salary. The suggested contribution field shows the minimum rate to capture full match when you fall short.

Real-world examples

1. Capturing full match. Salary $85,000, contribute 6%, employer 100% match up to 3%, $42,000 balance, 25 years, 7% return, 3% salary growth. Projected balance grows substantially from contributions, match, and compounding—run the calculator for your plan's exact match formula.

2. Leaving match on the table. Same inputs but 2% employee contribution. Full match not captured; employer contributes less than maximum. Increasing to 3% may cost modest take-home pay but adds employer dollars immediately.

3. No employer match. Match rate 0%—projection reflects employee contributions and returns only. Compare increasing percentage vs. funding IRA or taxable accounts separately.

4. Late career boost. 10 years to retirement with higher salary and larger starting balance—contribution increases still matter but have less time to compound than at age 30.

Common mistakes

• Contributing below the match cap. The most cited 401(k) mistake is skipping free employer money.
• Using optimistic return assumptions only. Long-term averages are not yearly outcomes; stress-test lower returns.
• Ignoring plan fees. Expense ratios reduce net returns inside the projection.
• Confusing this with retirement readiness. Projected balance is one input; spending needs and other accounts complete the picture—use retirement projection for broader modeling.
• Forgetting IRS limits. High earners may hit annual deferral caps before maximizing match is an issue—verify plan rules.
• Not increasing contributions after raises. Percent-of-salary contributions auto-rise with salary; fixed dollar contributions do not.

When to use this calculator

Use this calculator when starting a job, reviewing open enrollment, or asking whether your contribution rate captures full employer match. It also helps compare increasing 401(k) deferrals against other uses of cash when you know your plan's match formula.

Read compound growth basics for how time and return interact. See inflation and savings for real purchasing power of future balances. For full retirement planning beyond match mechanics, use the retirement projection calculator.

Frequently asked questions

What is a 401(k) employer match? An employer match is a contribution your employer adds to your 401(k) based on how much you contribute. A common formula is a 100% match on up to 3% of salary — meaning if you earn $80,000 and contribute 3% ($2,400), your employer adds another $2,400. Match formulas vary widely: some plans offer 50 cents per dollar up to 6%, others use tiered structures. Always check your Summary Plan Description or HR portal for your plan's exact formula before using this calculator.

What happens if I contribute more than the amount needed to get the full match? Contributions above the match cap continue growing tax-deferred in your account, but they do not generate additional employer money. The calculator separates the minimum needed to capture full match from your actual contribution so you can evaluate whether exceeding the cap makes sense given other financial goals — paying off high-rate debt or funding a Roth IRA, for example.

Does the calculator account for IRS annual contribution limits? No. The model projects contributions without capping them at IRS limits. For 2024, the employee contribution limit is $23,000, with an additional $7,500 catch-up contribution allowed for workers age 50 and older. High earners or those running large contribution percentages on high salaries should verify they will not hit the annual ceiling before year-end.

What is vesting and why does it matter for employer match? Vesting determines when employer contributions legally belong to you. Immediate vesting means employer match is yours from day one. Cliff vesting requires a period of employment — often two to three years — before any employer contributions vest at all. Graded vesting releases employer money incrementally over several years. This calculator assumes all contributions are fully vested, so factor vesting schedules into your evaluation if you might leave before full vesting is reached.

How does annual salary increase affect the long-term projection? When you enter a positive salary growth rate, the calculator raises your annual salary once per year by that percentage. Because contributions are a percentage of salary, monthly employee and employer dollar amounts grow over time alongside your compensation. This reflects an important benefit of percentage-based contribution plans — your savings rate stays consistent while the actual dollar amount increases with your pay each year.

Should I prioritize my 401(k) or pay off debt first? A widely used framework: always contribute enough to capture full employer match first — that match represents an immediate 50–100% return on that portion of contribution that is very difficult to match elsewhere. Beyond capturing full match, high-rate debt above roughly 6–7% often carries an effective return from payoff that exceeds expected investment gains. Once high-rate debt is resolved, increasing contributions to the IRS limit or funding other accounts like a Roth IRA are typically next priorities. The debt payoff calculator and retirement projection calculator together help model this trade-off against your full financial picture.

Related calculators

Model broader retirement savings with the retirement projection calculator — project long-horizon balances with monthly contributions and optional inflation-adjusted views in today's dollars. Explore how compounding and contributions interact with the compound interest calculator. Set non-retirement savings targets by deadline with the savings goal calculator. Summarize investment performance on a past or current investment with the ROI calculator. Adjust future balances for purchasing power with the inflation calculator.