How to Use This Calculator
Start by entering your current age and retirement age. Then enter your current 401(k) balance — the sum of all 401(k) accounts if you have more than one — and your annual salary before taxes.
In the Your Contribution field, enter the percentage of your salary you contribute each paycheck. If you contribute $400 per month on a $80,000 salary, that is 6% of your salary ($400 × 12 = $4,800, and $4,800 ÷ $80,000 = 6%). The calculator will automatically cap your contribution at the 2025 IRS limit of $23,500/year ($31,000 if you are 50 or older).
For the employer match fields, enter your match rate (what percentage of each dollar you contribute your employer matches) and your match cap (the maximum percentage of your salary that is eligible for matching). The most common structure in the U.S. is a 100% match up to 3% of salary — enter 100% for the rate and 3% for the cap. If your employer matches 50 cents per dollar up to 6% of salary, enter 50% and 6%. Set both fields to 0 if your employer offers no match.
Click Calculate 401(k) Balance to see your projected balance, the breakdown of contributions vs. employer match vs. investment gains, and a year-by-year table. Open the Salary Growth & Inflation section to model a rising salary over your career, which increases both your contributions and your employer match over time.
How a 401(k) Works
A 401(k) is an employer-sponsored retirement savings plan governed by Section 401(k) of the U.S. Internal Revenue Code. It allows employees to contribute a portion of their salary to a tax-advantaged investment account, reducing their current taxable income (Traditional 401k) or locking in tax-free growth (Roth 401k).
Contributions are deducted directly from your paycheck before or after taxes, depending on plan type, and invested in a selection of mutual funds, index funds, or target-date funds offered by your employer's plan. Your investments grow tax-deferred (Traditional) or tax-free (Roth) until withdrawal in retirement — at which point you begin drawing income to replace your working-years salary.
The 401(k)'s primary advantages over taxable investing are:
- Tax deferral (Traditional): You pay no tax on contributions or investment gains until withdrawal, allowing your full pre-tax dollar to compound rather than a dollar reduced by your marginal rate.
- Tax-free growth (Roth): Contributions are after-tax, but all growth and qualified withdrawals are completely tax-free — including decades of compounded returns.
- Employer match: Free money added by your employer, typically matching 50%–100% of your contributions up to a defined limit. This is an immediate, guaranteed return unavailable in any other investment vehicle.
- Creditor protection: 401(k) assets are generally protected from creditors in bankruptcy proceedings under federal law.
Withdrawals from a Traditional 401(k) before age 59½ trigger a 10% penalty plus ordinary income tax. After 59½, withdrawals are penalty-free but taxed as ordinary income. At age 73, you must begin taking required minimum distributions (RMDs) annually, calculated based on your account balance and IRS life expectancy tables. Roth 401(k)s are subject to RMDs unless rolled into a Roth IRA before retirement.
The Formula: How Your Balance Is Projected
This calculator uses a month-by-month compound interest simulationthat adds both your employee contributions and your employer match each period, then applies investment earnings on the growing balance. The core formula for one month is:
Interest = Balance × (Annual Return ÷ 12)
New Balance = Balance + Interest + (Employee Contribution + Employer Match) ÷ 12
Across all 12 months of a year, this produces a year-end balance. The simulation repeats for each year until retirement, with your salary optionally growing by the annual salary growth rate — which in turn increases both your dollar contribution and your employer match.
Example: Age 30, retiring at 67 (37 years). Current balance: $25,000. Annual salary: $80,000. Employee contribution: 6% ($4,800/year). Employer match: 100% up to 3% of salary ($2,400/year). Combined annual contribution: $7,200. Expected return: 7%.
Monthly rate: 7% ÷ 12 = 0.5833%
Monthly contribution: $7,200 ÷ 12 = $600
Year 1 starting balance: $25,000
Year 1 interest: $25,000 × 7% ≈ $1,750
Year 1 ending balance: $25,000 + $1,750 + $7,200 ≈ $33,950
…
Projected balance at 67: ≈ $1,350,000
The employer match alone — $2,400/year growing at 7% for 37 years — compounds to approximately $400,000 of the final balance. This is money that cost you nothing beyond choosing to contribute at least 3% of your salary.
Employer Match: The Most Underused Benefit in America
Employer matching is the single most powerful financial benefit available to most working Americans, yet surveys consistently find that 20%–25% of employees who have access to a 401(k) match do not contribute enough to capture the full match. That is leaving guaranteed, risk-free money on the table.
Consider the math of a standard 100%-match-up-to-3% structure on a $70,000 salary:
| Your Contribution | Your Annual $ | Employer Match | Immediate Return |
|---|---|---|---|
| 1% of salary | $700 | $700 | 100% |
| 2% of salary | $1,400 | $1,400 | 100% |
| 3% of salary | $2,100 | $2,100 | 100% |
| 4% of salary | $2,800 | $2,100 | 75% |
| 6% of salary | $4,200 | $2,100 | 50% |
Contributing 3% earns a 100% immediate return on that 3% — the best guaranteed return in personal finance. Contributing above the match cap (say, 6% when the cap is 3%) still grows tax-deferred, but those additional dollars earn only the market return, not a match bonus.
Over a 35-year career, the compounded value of a $2,100/year employer match growing at 7% is approximately $310,000. An employee who contributes below the match threshold gives up $310,000 of their retirement security — the equivalent of almost 4.5 years of a $70,000 salary — simply because they did not select a high enough contribution rate. Capturing the full employer match is the first, non-negotiable step in retirement planning.
IRS Contribution Limits for 2025
The IRS sets annual limits on how much can be contributed to 401(k) accounts to prevent high earners from using them as unlimited tax shelters. The limits for 2025 are:
- Employee elective deferral limit: $23,500/year for employees under age 50. This is the cap on your own salary reduction contributions, regardless of your employer's contributions.
- Catch-up contribution limit (age 50–59 and 64+): An additional $7,500/year, bringing the total to $31,000/year. This allows those approaching retirement to accelerate savings in the final years.
- Super catch-up contribution (age 60–63): SECURE 2.0 Act introduced a higher catch-up of $11,250 for this age range, bringing the total to $34,750/year in 2025.
- Overall plan limit (415(c) limit): Total annual additions (employee + employer contributions + forfeitures) cannot exceed $70,000 in 2025 ($77,500 for those 50+).
This calculator applies the standard employee limits automatically: $23,500 for employees under 50, and $31,000 for employees 50 and older. The IRS adjusts these limits annually for inflation, typically in October for the following year.
How Much Should You Contribute?
There is a clear prioritization order for retirement savings. Following it ensures you capture the highest-value dollars first:
Step 1: Contribute enough to get the full employer match. This is always the first priority, regardless of whether you have debt or other financial goals. A 50% or 100% match is a guaranteed, immediate return that no other investment can match.
Step 2: Max an HSA if eligible. If you have a high-deductible health plan, a Health Savings Account offers a triple tax advantage: deductible contributions, tax-free growth, and tax-free withdrawals for medical expenses. After 65, withdrawals for any purpose are taxed as ordinary income — making it function as a secondary retirement account.
Step 3: Max a Roth IRA if eligible. The Roth IRA ($7,000/year in 2025, $8,000 if 50+) offers more investment flexibility and no required minimum distributions, making it an excellent complement to a 401(k) for tax diversification. Income limits apply: phaseout begins at $150,000 for single filers and $236,000 for married filers in 2025.
Step 4: Max the 401(k). After capturing the match and contributing to an HSA and Roth IRA, direct additional savings back to the 401(k) up to the annual limit. The tax deferral (or tax-free growth in a Roth 401k) on large amounts is a significant long-term advantage.
A common guideline is a total savings rate of 15% of gross income for retirement (including employer contributions). For someone earning $80,000 with a 3% employer match, that means contributing 12% of salary ($9,600/year) to reach a combined 15% ($12,000/year). This is a reasonable target for someone starting at age 25–30 who wants to retire by their late 60s.
The Cost of Early Withdrawal
Withdrawing from a 401(k) before age 59½ is one of the most financially damaging decisions in personal finance. The cost has two parts: immediate taxes and penalties, and permanent loss of compound growth.
Immediate cost: A 10% early withdrawal penalty applies on top of ordinary income tax. For someone in the 22% federal bracket, that is a combined 32% federal hit — and most states add additional income tax. On a $50,000 withdrawal, you might net only $30,000–$34,000 after federal and state taxes.
Permanent compound growth loss: The more lasting damage is the loss of future compounding. $50,000 withdrawn at age 35 would have grown to approximately $380,000 by age 67 at a 7% return. The penalty and taxes cost $16,000–$20,000 immediately. The lost compounding costs $330,000+ over the next 32 years.
The table below shows the total true cost of cashing out different amounts at age 35:
| Withdrawal Amount | Tax + Penalty (~32%) | Lost Compounding at 67 | Total True Cost |
|---|---|---|---|
| $10,000 | $3,200 | $76,000 | $79,200 |
| $25,000 | $8,000 | $190,000 | $198,000 |
| $50,000 | $16,000 | $381,000 | $397,000 |
| $100,000 | $32,000 | $762,000 | $794,000 |
If you need liquidity, a 401(k) loan is far preferable to a withdrawal: you can borrow up to 50% of your vested balance (max $50,000), repay yourself with interest (typically prime + 1%), and avoid the penalty entirely. The risk is that if you leave your employer, the outstanding loan balance typically becomes due within 60–90 days or is treated as a taxable distribution.
Roth 401(k) vs. Traditional 401(k)
Both options are available in most modern 401(k) plans, and the choice between them is one of the most consequential decisions in retirement planning. The difference is entirely about timing of taxation:
Traditional 401(k): Contributions reduce your taxable income today (a pre-tax deduction). Investments grow tax-deferred. Withdrawals in retirement are taxed as ordinary income. Best when you are currently in a high tax bracket and expect a lower rate in retirement.
Roth 401(k): Contributions are made with after-tax dollars (no deduction today). Investments grow tax-free. Qualified withdrawals in retirement — including all growth — are completely tax-free. Best when you are currently in a lower tax bracket and expect rates to be higher in retirement, or when you expect your income to grow significantly.
The Roth 401(k) has no income limits (unlike the Roth IRA, which phases out for high earners), so high-income earners who are ineligible for a Roth IRA can still access Roth benefits through their employer plan. Roth 401(k)s are subject to required minimum distributions starting at age 73, unlike Roth IRAs — a reason many advisors recommend rolling a Roth 401(k) to a Roth IRA before retirement.
A practical approach for most earners: contribute Traditional up to at least the employer match (capturing the match with pre-tax dollars), then consider splitting remaining contributions between Traditional and Roth for tax diversification in retirement — creating flexibility to draw from taxable and tax-free buckets strategically based on each year's income situation.
Frequently Asked Questions
How much should I contribute to my 401(k)?
Always contribute at least enough to capture the full employer match — that is an immediate 50%–100% risk-free return that no other investment can replicate. Beyond the match, most financial planners target a total savings rate of 15% of gross income (including employer contributions). For an employee earning $75,000 with a 3% employer match, this means contributing about 12% of salary yourself ($9,000/year) to reach a combined 15%. Those starting in their 40s may need 20%–25% to reach the same retirement balance. Use the calculator above to find your personal target: enter your current savings and adjust the contribution percentage until the projected balance supports your retirement income goal.
What is employer match and how does it work?
An employer match is a contribution your company makes to your 401(k) based on what you put in. The most common U.S. structure is a 100% match up to 3% of salary: for every dollar you contribute (up to 3% of your salary), your employer adds another dollar. On a $70,000 salary, that is $2,100/year in free money — assuming you contribute at least 3%. Some plans use a partial match (e.g., 50% match up to 6% of salary), where you must contribute 6% to get the maximum match of 3% of salary. Employer match is subject to vesting: you may need to stay employed 1–6 years before those dollars are fully yours.
What is the 401(k) contribution limit for 2025?
For 2025, employees can contribute up to $23,500 of their own salary to a 401(k). Employees who are age 50 or older can contribute an additional $7,500 as a catch-up contribution, for a total of $31,000. Employees aged 60–63 have a higher catch-up limit of $11,250 under the SECURE 2.0 Act, bringing their total to $34,750. These limits apply to both Traditional and Roth 401(k) contributions combined. The overall plan limit including employer contributions is $70,000 ($77,500 for those 50+). The IRS adjusts these limits annually for inflation.
What is a good annual return to assume?
For a portfolio heavily weighted toward equity index funds, 7% nominal is a widely used conservative assumption for long-term retirement planning. The S&P 500 has historically returned 9%–10% nominally, but many planners discount this by 2%–3% to account for potentially lower future returns, fees, and behavioral drift. A blended portfolio (70% stocks, 30% bonds) might reasonably use 5%–6%. A target-date fund 30 years from retirement typically holds 85%–90% equities and historically returns 7%–8%. The safest approach is to model at multiple rates — 5%, 7%, and 9% — to understand the range of outcomes before committing to a savings plan.
What happens to my 401(k) if I change jobs?
You have four options: roll it to your new employer's 401(k), roll it to an IRA, leave it in the old plan (if the balance exceeds $5,000 and the plan allows it), or cash it out. Cashing out triggers a 10% penalty plus ordinary income tax — losing 30%–40% of the balance immediately. Always roll over. A direct rollover (trustee-to-trustee) avoids any withholding or tax consequences entirely. If you receive a check made out to you, you have 60 days to deposit it in a qualified retirement account; any amount not deposited is treated as a distribution subject to taxes and penalties.
Can I contribute to both a 401(k) and an IRA?
Yes. Contributing to a 401(k) does not prevent you from also contributing to an IRA. For 2025, the IRA contribution limit is $7,000/year ($8,000 if 50+). However, if you (or your spouse) are covered by a workplace retirement plan, your Traditional IRA deduction phases out at higher incomes: for single filers covered by a workplace plan, the phaseout range is $79,000–$89,000 in 2025. The Roth IRA phaseout for single filers is $150,000–$165,000. If your income is above these thresholds, you can still make non-deductible Traditional IRA contributions or consider a backdoor Roth IRA conversion.
Roth 401(k) vs. Traditional 401(k) — which is better?
The better choice depends on whether you expect to be in a higher or lower tax bracket in retirement. If you are early in your career in the 22% bracket or lower, Roth contributions lock in a low rate on potentially 40 years of tax-free growth — an enormous advantage. If you are in your peak earning years in the 32%–37% bracket, the Traditional 401(k) deduction is worth more now, and you may retire in a lower bracket. A practical middle ground: contribute Traditional to get the full match, then put remaining contributions in Roth — this creates tax diversification that lets you control your taxable income in retirement.
What is vesting and how does it affect my match?
Vesting determines when employer contributions become fully yours. Your own contributions are always 100% yours immediately. Employer match may be subject to a vesting schedule — either cliff vesting (0% until a certain tenure, then 100%) or graded vesting (e.g., 20% per year for 5 years). If you leave before being fully vested, you forfeit unvested employer contributions. When evaluating a job change, check your vesting schedule: leaving 6 months before a cliff vest could mean forfeiting years of matched contributions. This is a negotiating point in offers — some employers offer faster vesting to attract candidates.
Methodology & Data Sources
This calculator uses a month-by-month compound interest simulation. Each month, investment earnings (balance × monthly rate) are added first, then the total monthly contribution (employee + employer, divided by 12) is deposited. The employer match is computed each year as: min(employee contribution × match rate, salary × match cap). IRS contribution limits are applied annually based on the participant's age at the end of each projected year: $23,500 for those under 50, $31,000 for those 50 and older (2025 IRS Publication 560, SECURE 2.0 Act amendments). If salary growth is specified, the salary increases at the start of each year after the first, compounding contributions and matches upward over the career.
The estimated monthly retirement income is calculated using the 4% rule: annual income = projected balance × 0.04, divided by 12. This rule is based on the Trinity Study (Cooley, Hubbard, Walz, 1998) and Bengen (1994), which found a 4% initial withdrawal rate adjusted annually for inflation to be sustainable over a 30-year retirement across most historical market conditions. It should be used as a planning benchmark, not a guarantee.
Historical return data for U.S. equities references long-run S&P 500 total return data compiled by Robert Shiller (Yale University) and Aswath Damodaran (NYU Stern). IRS contribution limits are sourced from IRS.gov (Revenue Procedure 2024-25 for 2025 limits). All calculations assume a fixed rate of return and do not account for fund fees, investment volatility, taxes on withdrawals, or changes in contribution amounts during the accumulation period. This calculator is provided for educational and planning purposes only and does not constitute financial advice.