About the 401K Calculator
401K Calculator helps estimate the key numbers involved in retirement decisions. It is designed for quick scenario comparison: enter a realistic set of values, calculate the result, then change one assumption at a time to see what has the greatest effect. Unlike a static table, the result responds to your inputs and keeps the calculation in your browser. Amounts are displayed in U.S. dollars for consistency, but the mathematical formulas can be used with another currency when every monetary input uses that same currency.
How to use this calculator
Enter values that match your situation and select Calculate result. Review the main result and its supporting figures, then change one input at a time to compare scenarios. Results are rounded for readability while the calculation retains additional precision internally.
Information you will need
- Starting amount
- Monthly contribution
- Annual return
- Years
How the calculation works
Projects growth with monthly compounding and contributions. Read the primary result together with the supporting values rather than focusing on one number alone. A useful estimate should make its assumptions visible. If the answer looks surprising, verify the unit, rate, time period, and whether the entered value is gross or net. Run a conservative and an optimistic scenario to understand the range of possible outcomes.
Formula or method
FV = P(1+r)n + C((1+r)n - 1)/r.
Worked example
$10,000 + $250/month at 7% for 10 years.
The example is illustrative rather than a recommendation. Use your own verified values and keep all monetary or measurement units consistent. When comparing alternatives, save or note each result so the assumptions do not become mixed.
How to interpret the result
The primary output answers the main question posed by the 401k calculator, while the additional cards provide context. A result with many decimal places is not necessarily more certain. The displayed precision makes comparison easier, but uncertainty in the inputs can be larger than the rounding difference.
Compare the result with a second scenario using a less favorable rate, return, cost, or time period. This sensitivity check often provides more useful planning information than one best-case projection.
Limitations and important notes
The 401k calculator is a planning tool, not a quote, filing calculation, lending decision, or promise of future performance. It does not automatically retrieve live market rates or apply every fee, tax bracket, program rule, product limit, or state law. Rules for products such as FHA, VA, Social Security, retirement accounts, and taxes can change. Confirm time-sensitive values with the lender, plan administrator, IRS, SSA, or another relevant authority before acting.
Frequently asked questions
What is the 401(k) contribution limit for 2025?
For 2025, you can contribute up to $23,500 to a 401(k), and workers age 50 and older can add a $7,500 catch-up, for a total of $31,000. Starting in 2025, the SECURE 2.0 Act allows workers ages 60 to 63 a higher catch-up of $11,250. The limit rises to $24,500 for 2026. Employer matching contributions do not count toward your personal limit but are capped by the total combined limit, which is around $70,000 for 2025. These figures are adjusted annually for inflation, so always check the current year.
How does a 401(k) employer match work?
An employer match is free money added to your account, usually calculated as a percentage of your contribution up to a cap. A common formula is 50 percent of your contributions up to 6 percent of salary, meaning if you earn $100,000 and contribute 6 percent ($6,000), your employer adds $3,000. Many companies match 3 to 5 percent of pay. Financial advisors generally recommend contributing at least enough to capture the full match, since missing it means leaving part of your compensation on the table.
Should I take a loan from my 401(k)?
A 401(k) loan lets you borrow up to 50 percent of your vested balance, capped at $50,000, and you repay yourself with interest. The main advantages are no credit check and interest paid to your own account. The risks are significant: if you leave or lose your job, the full balance is often due within 60 to 90 days or it counts as a taxable distribution with a 10 percent penalty if you are under 59 1/2. Most experts recommend exhausting emergency savings and other options before borrowing from your retirement.
What happens to my 401(k) when I change jobs?
You have several options when leaving a job: leave the money in your old employer's plan, roll it into your new employer's 401(k), move it to a traditional IRA, or cash it out. Cashing out is usually the worst choice because you pay income tax plus a 10 percent penalty if you are under 59 1/2. A direct rollover to an IRA or new plan keeps your money growing tax-deferred with no penalty. Be careful to use a direct trustee-to-trustee transfer so the check is not made out to you.
When can I withdraw from my 401(k) without penalty?
You can take penalty-free withdrawals from a 401(k) after age 59 1/2, though the money is still taxed as ordinary income. A special rule allows penalty-free withdrawals starting at age 55 if you separate from service in the year you turn 55 or later. Exceptions also cover disability, medical expenses over 7.5 percent of adjusted gross income, and certain hardship cases. Even without the 10 percent penalty, withdrawing early reduces your future growth, so many advisors treat 401(k) money as a last resort before age 59 1/2.
How much will my 401(k) be worth at retirement?
A 401(k) balance at retirement depends on how much you contribute, your employer match, and the return you earn. For example, contributing $10,000 a year with a $3,000 employer match over 30 years at a 7 percent average return grows to roughly $1.2 million. Most planners model 6 to 8 percent nominal returns, reflecting a portfolio weighted toward stocks over a long career. A 401(k) calculator can show how even small monthly increases and matching contributions compound into a much larger retirement balance.
What is the difference between a Roth and traditional 401(k)?
A traditional 401(k) gives you a tax deduction now, and you pay ordinary income tax on withdrawals in retirement. A Roth 401(k) offers no upfront deduction, but qualified withdrawals are tax-free, including growth. For 2025 and 2026, the contribution limits are identical, but employer matches are always made on a pretax basis, even in a Roth plan. Since 2024, the SECURE 2.0 Act no longer requires RMDs from Roth 401(k) accounts, making them more attractive. Your choice depends on whether you expect a higher or lower tax rate in retirement.