401k Calculator
Monthly compounding of balance plus deferrals — not a loan or withdrawal page. Click any i for detail.
401(k) growth
Current balance ($)
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Balance
What is in the 401(k) today. |
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Annual employee contribution ($)
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Employee
Your elective deferral for a typical year, before catch-up rules. |
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Annual employer contribution ($)
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Employer
Match or nonelective dollars. 0 if none. |
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Years to grow
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Years
How many years of contributions and compounding. |
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Assumed annual return (%)
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Return
You type the rate. No live market feed. |
How to use this calculator
- Enter today's 401(k) balance.
- Add annual employee and employer contribution dollars.
- Set years to grow and an assumed return percent.
- Read projected balance; fees and limits are not modeled.
Results explained
Monthly compounding adds (employee+employer)/12 each month. IRS deferral limits, vesting, and loan balances are out of scope.
Quick reference: 401(k) growth sketch
Monthly: balance grows by return, then contributions add.
| Item | Detail |
|---|---|
| Compounding | monthly on balance |
| Contributions | (employee + employer) / 12 per month |
| Return | you type the rate; no market feed |
| Catch-up | raise employee $ if age 50+ rules apply |
Not tax, investment, or plan document advice.
How the estimate is built
each month: bal ← bal×(1+r/12) + annual_contrib/12.
Example scenario
$45k start, $11.5k employee + $3.45k employer, 7%, 20 y → see live projected balance.
FAQ
Does this include employer match formulas?
No. Enter employer dollars you expect annually, not match percent rules.
Roth vs traditional?
Tax treatment differs; this page projects balance only, not after-tax spendable dollars.
What about loans and withdrawals?
Loan and penalty pages model those separately; they are not subtracted here.