Enter your current 401(k) balance, salary, contribution rate, and employer match to project your balance at retirement.
How to Use the 401(k) Calculator
Start with your current 401(k) balance, annual salary, and the percentage of salary you're contributing. Then enter your employer's match rate and match cap — most plans match a percentage of every dollar you contribute, up to some percentage of your salary — followed by an expected annual return and the number of years until retirement. The projection updates automatically as you adjust any field.
A 401(k) balance doesn't grow the way a lump sum does. Money lands every pay period, gets invested immediately, and compounds monthly rather than annually — so this calculator runs the same kind of month-by-month loop as a mortgage amortization schedule, just building a balance up instead of paying one down.
Employee Monthly = Annual Salary × Contribution % ÷ 12
Employer Monthly = Annual Salary × min(Contribution %, Match Cap %) × Match % ÷ 12
Balance(next month) = Balance × (1 + Monthly Return) + Employee Monthly + Employer MonthlyThe Match Cap Quietly Limits How Much Free Money You Get
Contribute past your plan's match cap and every additional dollar still grows tax-deferred, but the employer stops adding anything on top of it. A plan that matches 50 cents per dollar up to 6% of salary pays out the same employer contribution whether you're putting in 6% or 15% — the extra 9% is entirely your own money. That's why this calculator applies the match only up to whichever is smaller: your actual contribution rate or the cap.
Traditional 401(k) contributions come out of your paycheck before income tax is calculated, which is why deferring more into the plan lowers your taxable income today — the trade is that withdrawals in retirement are taxed as ordinary income, no different from a paycheck.
The gap between what you and your employer put in, versus what the account is actually worth at retirement, is the "Total Growth" figure — every dollar of it came from the market, not a paycheck.
Check the Actual IRS Contribution Limit Before Assuming Your Rate Is Achievable
The IRS caps how much an employee can contribute to a 401(k) in a given year with a flat dollar limit, and that limit typically rises with inflation each year — enough that a contribution rate expressed as a percentage of a high salary can exceed the actual dollar cap long before retirement. This calculator doesn't enforce that ceiling, since it changes annually and depends on your specific salary; check the current limit at irs.gov before assuming a given contribution percentage is legally allowed at your income level.