Free 401(k) Calculator

Your 401(k) Projection

The results card updates as you type and reports three separate things. Keeping them apart is what makes this a 401k retirement calculator rather than a generic savings projection.

Below those sits the line that matters most on this page: whether your current contribution rate captures the full match your formula allows. If it does not, the calculator tells you exactly how much employer money you are leaving behind each year.

Until you enter a return, only the contribution figures appear — those are arithmetic and need no assumption. Everything growth-dependent stays blank, because this page will not invent a market return on your behalf. Open View Full Breakdown to separate your own money from the employer's, see the growth component on its own, and check what would be yours today given your vesting percentage.

What Is a 401(k)?

A 401(k) is a retirement savings plan offered through an employer. You choose a percentage of your pay to contribute, it is deducted from your paycheck automatically, and the money is invested in the options your plan provides. Many employers add money of their own on top, which is the match.

Three features make it different from saving in an ordinary account:

• It is payroll-deducted. The money never reaches your checking account, which removes the monthly decision to save and is why participation rates are so much higher than for voluntary saving.
• It is tax-advantaged. Traditional contributions generally reduce your taxable income in the year you make them, and the account grows without annual tax on gains.
• It may come with employer money. No other savings vehicle available to most employees adds an immediate return simply for participating.

There are trade-offs. The money is intended for retirement, so withdrawing early generally triggers tax and penalties. Your investment choices are limited to what the plan offers, and those options carry fees that vary considerably between plans. Contributions are also capped annually by the IRS.

This page is a 401k growth calculator for the accumulation phase — what the balance could become while you are still working. For the wider question of whether that balance produces enough income to live on, use our retirement calculator, which covers all your retirement savings together.

How the Employer Match Works

The match is the single most valuable feature of most 401(k) plans, and it is the reason an employer match calculator is worth running before you set your contribution rate. The mechanism is simple: your employer adds money based on what you contribute, up to a stated ceiling.

Common match formulas

Formulas are usually written as a percentage of your contribution, applied only to contributions up to a percentage of your salary. Two common shapes, given here purely to show how the arithmetic works:

• "50% up to 6%" — the employer adds fifty cents per dollar you contribute, counting your contributions up to 6% of pay. Contributing 6% captures the full match; contributing 10% does not increase it.
• "100% up to 3%" — dollar for dollar, but only on the first 3% of pay. A smaller ceiling, but a higher rate on the money it covers.

These are illustrations of the structure, not anyone's actual terms. Your plan documents or HR team will tell you the formula that applies to you, and some plans use tiered or graded formulas that do not fit either shape.

Vesting schedules

Vesting determines when the employer's contributions actually become yours. Your own contributions are always fully yours from the first paycheck; the employer's portion may not be. Plans commonly vest employer money immediately, all at once after a set period, or gradually across several years of service.

This matters most when you are thinking about changing jobs. Leaving before you are fully vested can mean forfeiting part of the employer money in your account, which is worth checking before you hand in a resignation. The vesting field above applies your percentage to the employer portion only, so you can see what would genuinely be yours.

Annual contribution limits are set by the IRS

There is a cap on how much you can contribute each year, and a separate allowance for catch-up contributions once you reach a qualifying age. Both are set by the IRS and adjusted from time to time.

We deliberately do not print those figures on this page. Any number published here would eventually be wrong, and a stale contribution limit is exactly the kind of detail that causes real problems. Check the current figures on the IRS 401(k) contribution limits page, which is the authoritative source and is updated when the limits change.

How Your Contribution Rate Changes the Result

This is where how much should I contribute to my 401k stops being abstract. The table below uses your own figures — your salary, your match formula, your time frame — and varies only the contribution rate.

Watch the third column. It rises with your contribution only until you reach the match ceiling, then stops completely. That flat point is the most important number in your plan: below it you are declining part of your pay, above it every extra dollar is purely your own saving.

The fourth column keeps climbing, because your own contributions still compound. Both facts are true at once — the match has a hard limit, and saving beyond it is still worthwhile. Our guide to saving for retirement in your 30s covers how to raise a contribution rate gradually without feeling it.

Traditional vs Roth 401(k)

Many plans offer both a traditional and a Roth option inside the same 401(k). The investment choices are usually identical; what differs is when the money is taxed.

The underlying question is whether you would rather take the tax break now or later, which depends on your tax rate today compared with your expected rate in retirement — something nobody can know with certainty. That uncertainty is itself an argument some people use for holding both.

This calculator does not model tax, so it treats both the same. The eligibility rules, limits and withdrawal conditions for each are set by the IRS, and a tax professional is the right person to ask about your own situation.

401(k) vs Roth IRA: Which Should You Use?

These are different kinds of account, not competing versions of the same thing, and most people end up using both. A 401(k) comes through an employer and may carry a match; a Roth IRA is opened by you, independently of any job.

A widely used sequence is to contribute to the 401(k) up to the full employer match first, since that is the one return available to you with no market risk attached, then decide where additional savings are best placed. After the match, the choice turns on fees, investment options and tax treatment rather than on any universal rule. Our Roth IRA calculator models the after-tax side and sets a Roth against an equivalent traditional IRA.

Contribution limits and the income thresholds that govern Roth IRA eligibility are set annually by the IRS, so check them there rather than relying on figures quoted elsewhere — including here. For the combined picture across every account you hold, the retirement calculator projects them together and tests the result against a target income.

How to Use This 401(k) Calculator

1. Enter your annual salary before tax and before deductions.
2. Set your contribution percentage. This is the share of pay you defer into the plan each period.
3. Enter your employer's match formula in the two fields — the match rate, and the percentage of pay it applies up to. Replace the example values with your own plan's terms.
4. Add your current 401(k) balance if you already have one.
5. Choose an assumed annual return. The field is blank by design. Try a cautious figure as well as an optimistic one.
6. Set your current and retirement ages, then check the match line to see whether you are capturing everything your formula allows.

Read the match line before the balance. A large projected balance is satisfying, but unclaimed employer money is the one problem on this page you can fix immediately, and it costs nothing but a change to your deferral rate.

If you are unsure of your vesting percentage, leave it at 100% for the projection and check your plan documents separately — it affects what you would keep by leaving, not what the account grows to. Nothing you enter is stored or sent anywhere.

Our Methodology

The employer match is calculated as the match rate applied to your contributions, counting only contributions up to the match limit expressed as a percentage of salary: match = salary × min(your rate, limit) × match rate. That cap is why the match stops rising once you pass the ceiling, and the calculator applies it exactly rather than approximating.

The balance is projected with the standard future-value formula for a lump sum plus a regular deposit, compounded monthly: FV = P(1+r)ⁿ + M × ((1+r)ⁿ − 1) ÷ r, where M is your contribution and the employer match combined, divided into monthly deposits. The employer stream is also projected separately so we can report what the match alone is worth.

Before publication the match rule was cross-checked against an independently written implementation across 420 combinations of salary, contribution rate and match formula, and confirmed by hand against worked examples. The match was verified to be flat beyond the ceiling, the employee and employer streams proved additive, and the growth formula was checked against a month-by-month simulation and published annuity values. All currency is rounded to cents before display.

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