401(k) Calculator

Suppose you are 30 years old, earn $70,000, and contribute 6% of pay - that is $4,200 a year. Your employer matches 50% up to 6% of pay, adding another $2,100 a year. Starting from a $25,000 balance and assuming a 7% annual return with 2% raises, this 401(k) calculator projects you reach roughly $1.47 million by age 65. Of that, about $210,000 came from your own contributions, $105,000 from employer match, and over $1.1 million from compound growth - which is exactly why starting early matters so much. All contribution limits below are for tax year 2025. Once you have a target balance, the Retirement Calculator shows whether it will actually last through your retirement years.

2025 IRS contribution limits

The IRS sets how much you can defer into a 401(k) each year. For 2025:

The employer match is separate and does not count toward these employee limits. The calculator caps your contribution automatically once your chosen percentage would exceed the limit for your age.

The compounding formula

Each month the calculator grows the balance, then adds 1/12 of your annual contribution and 1/12 of the employer match:

where r is the monthly return (annual return ÷ 12). Repeated month after month, year after year, small contributions snowball - the longer the runway, the larger the share of your final balance that comes from growth rather than your own deposits.

Always capture the full employer match

An employer match is an immediate, guaranteed return on your money. If your plan matches 50% on the first 6% of pay, contributing less than 6% leaves part of that match unclaimed. The single most reliable way to boost your projected balance is to contribute at least enough to get every matched dollar before anything else.

How much should you contribute?

A widely cited target is to save around 15% of your gross pay for retirement, including the employer match. So if your employer matches up to 6% of pay, contributing 9% yourself gets you to roughly 15% combined. If 15% feels out of reach today, start at whatever percentage captures the full match, then raise your rate by one point each year - the calculator makes it easy to see how much each extra point adds to the final balance. The 2025 employee limit ($23,500) only becomes the binding constraint at higher salaries; for example, a 15% contribution on a $90,000 salary is $13,500, still well under the cap. To grow money outside the 401(k) once you have maxed the match, compare the outcome in the Investment Calculator.

Why steady contributions help in down markets

The projection assumes a smooth annual return, but real markets rise and fall. That volatility is not all bad for a saver who keeps contributing: because you buy more shares when prices are low and fewer when they are high, regular paycheck contributions automatically practice dollar-cost averaging. A down market early in your career can actually help the long-run balance, since those cheaply bought shares have decades to recover and compound. The biggest mistake is reacting to a downturn by cutting contributions or cashing out - that locks in losses and forfeits the rebound. Leave the projection's steady-return assumption as a long-run average and keep contributing through the dips.

Traditional vs Roth 401(k)

A traditional 401(k) is funded pre-tax and lowers your taxable income today, with withdrawals taxed as ordinary income later. A Roth 401(k) is funded after tax, and qualified withdrawals are tax-free. The 2025 employee limit is the same for both. This calculator projects the gross account balance and does not model the tax you'll owe on traditional withdrawals. If you want to compare tax-free growth in a separate account, the Roth IRA Calculator models a Roth specifically, and the IRA Calculator covers a traditional IRA.

How to use this 401(k) calculator

You only need a handful of numbers to get a realistic projection. Work through the fields in order:

1. Current age & retirement age: these set how many years your money has to compound. The gap between them is the single biggest driver of the final balance.
2. Current salary: your contribution and the employer match are both calculated as percentages of this figure.
3. Current 401(k) balance: enter what you already have saved, including any rollovers from previous employers. Enter 0 if you are just starting.
4. Contribution percentage: the share of pay you defer each year. The calculator caps it automatically at the 2025 IRS limit for your age.
5. Employer match: enter the match rate and the cap (for example 50% up to 6% of pay). This is added on top of your own contribution.
6. Expected return & salary growth: set a long-run annual return (7% is a reasonable default) and an annual raise assumption to grow future contributions.

The projected balance updates instantly. Read the headline figure at the top, then scroll the year-by-year table to see how your contributions, the match, and compound growth stack up over time.

Who this calculator is for

This tool is built for anyone trying to turn today's savings rate into a realistic retirement number. That includes:

• New savers deciding what contribution percentage to set on their first 401(k) enrollment.
• Mid-career workers checking whether they are on track and how much a higher contribution rate would change the outcome.
• Anyone weighing a raise who wants to see what funneling part of it into the 401(k) does to the final balance.
• Savers age 50+ who want to model the impact of catch-up contributions on their remaining working years.
• People comparing job offers where one employer's match is more generous than another's.

A second worked example: starting later but saving more

Suppose you are 45, earn $90,000, and already have $150,000 saved. You contribute 10% of pay ($9,000 a year) and your employer matches 50% up to 6% (another $2,700 a year). Assuming a 7% return and 2% raises, this calculator projects roughly $1.2 million by age 65. Notice the contrast with the age-30 example above: even though you start with a large $150,000 head start and save more than twice as much per year, the shorter 20-year runway means your new contributions have far less time to compound - on their own they add only about $590,000, while the same dollars saved from age 30 would grow far more. That is the clearest illustration of why a modest contribution started early can rival a large contribution started late - and why, if you are starting later, maximizing both your rate and your catch-up contributions matters even more.

Key 401(k) terms explained

• Elective deferral: the money you choose to redirect from your paycheck into the 401(k). The 2025 employee limit ($23,500) applies to this.
• Employer match: money your employer adds based on what you contribute, up to a cap. It does not count against your employee deferral limit.
• Vesting: the schedule that determines how much of the employer match you actually own. Your own contributions are always 100% vested; the match may vest gradually over several years.
• Catch-up contribution: an extra amount savers age 50+ can defer ($7,500 in 2025, or $11,250 for ages 60-63).
• Compounding: earning returns on your past returns, not just on your contributions. It is what makes the long-run balance so much larger than the sum you deposit.
• Rollover: moving a 401(k) balance into a new plan or an IRA without triggering taxes, typically when you change jobs.

What changes the result the most

If you adjust the inputs and watch the projection move, a few factors clearly dominate:

• Years until retirement: the most powerful lever - more time means dramatically more compounding.
• Contribution percentage: the part fully within your control; raising it even a point or two compounds into a large difference.
• Expected return: small changes swing the long-run balance a lot, which is why a conservative assumption is safer than an optimistic one.
• Employer match: free money that effectively boosts your savings rate at no cost to you.
• Starting balance: existing savings keep compounding the whole way, so rollovers and early balances carry a lot of weight.

Tips to improve your projected balance

• Capture the full match first. Contribute at least up to the match cap before anything else - it is the highest-return move available.
• Automate annual increases. Many plans let you raise your contribution by 1% each year automatically, so saving more keeps pace with raises painlessly.
• Use catch-up contributions at 50+. The extra limit lets you add meaningfully to the balance in your highest-earning years.
• Keep fees low. Choosing low-cost index funds inside the plan leaves more of your return compounding for you instead of going to fund expenses.
• Avoid early withdrawals. Pulling money out before age 59 1/2 usually triggers tax plus a 10% penalty and erases future compound growth on those dollars.

Limitations and assumptions

This calculator is a planning estimate, not a guarantee. Keep these assumptions in mind:

• It assumes a steady annual return every year; real markets are volatile and some years are negative.
• It projects the gross balance and does not subtract investment fees, plan administration costs, or the income tax owed on traditional 401(k) withdrawals.
• It does not adjust for inflation, so the final figure is in future dollars, which buy less than today's dollars.
• It assumes you keep contributing every year without gaps for job changes, leaves of absence, or hardship withdrawals.
• It uses the 2025 IRS limits throughout; in reality the limits are adjusted for inflation most years, which would let you contribute more over time.

How it compares to related calculators

This page answers "how big could my 401(k) grow?" If you have a different question, a sister tool fits better:

• To see whether your total savings will last through retirement, use the Retirement Calculator.
• To model a tax-free Roth account with its own income limits, use the Roth IRA Calculator.
• To project a traditional or general IRA, use the IRA Calculator.
• To grow a general (non-retirement) investment, use the Investment Calculator.
• To plan tax-advantaged medical savings alongside retirement, use the HSA Calculator.

Sources

• Internal Revenue Service (IRS) - 401(k) and profit-sharing plan contribution limits.
• Internal Revenue Service (IRS) - 401(k) limit increases to $23,500 for 2025.
• U.S. Department of Labor (DOL) - Types of retirement plans.