401k Calculator
Project your 401k retirement savings with employer matching, salary growth, and catch-up contributions. See your estimated balance, monthly retirement income, and how your money grows over time.
401k Basics: What You Need to Know
A 401(k) is an employer-sponsored retirement savings plan that lets you set aside money from your paycheck before taxes are taken out. The name comes from Section 401(k) of the Internal Revenue Code, which isn't exactly inspiring, but the benefits certainly are. When you contribute to a traditional 401(k), your taxable income drops by the amount you put in. If you earn $60,000 and contribute $6,000, you're only taxed on $54,000.
The money inside a 401(k) grows tax-deferred, meaning you won't pay taxes on dividends, capital gains, or interest until you withdraw the funds in retirement. This tax shelter allows your investments to compound more aggressively than they would in a regular brokerage account where you'd owe taxes each year on gains.
For 2024, the employee contribution limit is $23,000 if you're under 50, and $30,500 if you're 50 or older thanks to catch-up contributions. These limits apply only to your contributions — employer matching doesn't count against them. The total combined limit for employee and employer contributions is $69,000 ($76,500 with catch-up contributions).
You can generally start withdrawing from your 401(k) without penalty at age 59 and a half. Withdrawals before that usually trigger a 10% early withdrawal penalty on top of regular income taxes, though there are exceptions for hardship, disability, and certain other situations. Required minimum distributions kick in at age 73, meaning you eventually have to start taking money out whether you want to or not.
The Power of Employer Matching
If your employer offers a 401(k) match and you're not contributing enough to get the full match, you're leaving free money on the table. There's genuinely no gentler way to put it. Employer matching is the closest thing to a guaranteed return that exists in personal finance.
A common matching formula is 50% of employee contributions up to 6% of salary. If you earn $60,000 and contribute 6% ($3,600), your employer adds another $1,800. That's an immediate 50% return on your contributed dollars before any investment growth even happens. Some employers are more generous — dollar-for-dollar matches up to 4% or 5% aren't uncommon, especially in competitive industries.
The match often comes with a vesting schedule, which means you don't fully own the matched funds right away. A typical vesting schedule might give you 20% ownership after one year, 40% after two years, and so on until you're fully vested at five or six years. If you leave the company before you're fully vested, you forfeit the unvested portion of the employer match. Your own contributions are always 100% yours.
Here's a practical rule: before you invest anywhere else — before opening an IRA, before paying off low-interest debt, before investing in a taxable brokerage account — contribute enough to your 401(k) to capture the full employer match. The guaranteed return from matching beats almost any other investment decision you could make.
Contribution Limits and Catch-Up Contributions
The IRS sets annual limits on how much you can contribute to your 401(k), and these limits tend to increase slightly each year to keep pace with inflation. For 2024, the standard employee contribution limit is $23,000. If you're 50 or older, you can make an additional catch-up contribution of $7,500, bringing your personal limit to $30,500.
These limits are per person, not per account. If you change jobs during the year and have two 401(k) plans, your total contributions across both plans can't exceed the limit. You'd need to coordinate between the two employers to avoid over-contributing, which creates a tax mess.
Many people don't come close to maxing out their 401(k), and that's fine. Contributing what you can afford is far better than contributing nothing because the maximum feels unreachable. Even $200 per month from age 25 to 65, earning a 7% average return, grows to roughly $525,000. That's without any employer match.
If you're behind on retirement savings and over 50, catch-up contributions are specifically designed for you. The extra $7,500 per year might not sound like much, but at 7% returns, that adds approximately $105,000 over 10 years. Combined with the standard contribution, someone contributing the full $30,500 annually from ages 55 to 65 would add about $430,000 to their 401(k), even starting from zero. That's the power of consistent contributions paired with compound growth, even over a relatively short window.
Investment Allocation Strategies
Having a 401(k) is step one. Choosing how to invest the money inside it is step two, and it matters almost as much. Most 401(k) plans offer a menu of mutual funds covering different asset classes: domestic stocks, international stocks, bonds, and sometimes real estate or target-date funds.
The conventional wisdom is to invest more aggressively when you're young and gradually shift toward bonds and stable investments as you approach retirement. The logic is simple — if you're 30, you've got 35 years to ride out market downturns. If you're 60, a major crash right before retirement could seriously damage your plans. A rough guideline some advisors use is to subtract your age from 110 to get your stock allocation percentage. At 30, that's 80% stocks and 20% bonds. At 55, it's 55% stocks and 45% bonds.
Target-date funds automate this transition for you. A 2055 target-date fund is designed for someone planning to retire around 2055. It starts aggressive and automatically rebalances toward conservative holdings as the target year approaches. These funds are popular because they require zero maintenance — you pick the one closest to your expected retirement year and forget about it. The trade-off is slightly higher fees than building your own allocation with individual index funds.
Regardless of your approach, keep fees in mind. The difference between a fund charging 0.05% and one charging 1% might seem trivial, but over 30 years on a $500,000 balance, the expensive fund costs you roughly $130,000 more in fees. Low-cost index funds that track broad market indexes like the S&P 500 or total stock market have consistently outperformed the majority of actively managed funds after fees. If your 401(k) offers an S&P 500 index fund with low expenses, that alone is a solid foundation for a retirement portfolio.
How Salary Growth and Inflation Shape Your Retirement
Most 401k projections assume you contribute the same dollar amount every year for the rest of your career. But that's not how real life works. Salaries tend to rise over time through promotions, raises, and job changes. If you contribute 10% of a $60,000 salary today, that's $6,000. But if your salary grows to $90,000 over the next decade, that same 10% becomes $9,000 — a 50% increase in contributions without any extra effort on your part. Over a 35-year career with 3% annual raises, your final salary could be roughly $170,000. That means your contributions in the last decade of work are nearly triple what they were at the start.
This is one reason why percentage-based contributions work so well for 401k plans. You set a percentage once, and your contributions automatically scale with your income. It's built-in escalation without needing to remember to adjust anything.
Inflation is the other side of this coin. While your salary grows in nominal terms, the purchasing power of each dollar shrinks. The historical average inflation rate in the United States is about 3% per year. If your investments return 7% annually, your real return after inflation is closer to 4%. A projected balance of $1.5 million in 35 years sounds enormous, but in today's dollars it might be worth around $530,000. Still a significant sum, but a very different number.
This calculator lets you toggle on salary growth and inflation to see both sides of the picture. The inflation-adjusted output shows what your retirement balance will actually buy in today's prices. The estimated monthly income uses the 4% rule — a widely cited retirement guideline that suggests withdrawing 4% of your portfolio per year gives you a high probability of not running out of money over a 30-year retirement. On a $1.5 million balance, that's $60,000 per year or $5,000 per month before taxes.
401k Compound Growth
FV = PV(1+r)^n + Σ[C_i × (1+r)^(n-i)]
Your 401k balance grows through three sources: your contributions, your employer's matching contributions, and investment returns on the total balance. Each year, the current balance grows by the expected return rate, and new contributions (which may increase with salary growth) plus employer match are added. Over decades, compound growth becomes the dominant factor — the interest earned on previous interest creates exponential growth that accelerates over time.
Where:
- FV = Future value of the account at retirement
- PV = Present value (your current balance)
- C_i = Total contribution in year i (employee + employer match)
- r = Expected annual rate of return
- n = Number of years until retirement
Example Calculations
Starting at 30 with Employer Match
A 30-year-old earning $60,000 per year with $25,000 saved. Contributing 10% of salary with a 50% employer match up to 6% of salary, earning 7% annually until age 65.
- Years to retirement: 65 - 30 = 35 years
- Annual contribution: $60,000 x 10% = $6,000
- Employer match: $60,000 x 6% (match limit) x 50% = $1,800
- Total annual addition: $6,000 + $1,800 = $7,800
- Growth of current balance: $25,000 x (1.07)^35 = $266,863
- Growth of annual contributions: $7,800 x [(1.07)^35 - 1] / 0.07 = $1,078,200
- Total at retirement: approximately $1,345,063
The majority of the final balance comes from investment growth, not contributions. With salary growth enabled at 3%, the balance would be significantly higher as contributions increase each year.
Late Start at 45
A 45-year-old earning $85,000 with $50,000 saved. Contributing 15% of salary with a 100% employer match up to 4%, earning 7% annually until age 65.
- Years to retirement: 65 - 45 = 20 years
- Annual contribution: $85,000 x 15% = $12,750
- Employer match: $85,000 x 4% x 100% = $3,400
- Total annual addition: $12,750 + $3,400 = $16,150
- Catch-up contributions of $7,500/yr added starting at age 50
- Total at retirement: approximately $900,000+
Starting at 45 means fewer years of compound growth. Despite higher contributions, the final balance is lower than starting at 30. Catch-up contributions after age 50 add a meaningful boost.
Maximizing Catch-Up Contributions After 50
A 50-year-old earning $120,000 with $200,000 saved. Contributing 15% with catch-up contributions, 100% employer match up to 6%, earning 7% until age 65.
- Years to retirement: 65 - 50 = 15 years
- Annual contribution: $120,000 x 15% = $18,000 + $7,500 catch-up = $25,500
- Employer match: $120,000 x 6% x 100% = $7,200
- Total annual addition: $25,500 + $7,200 = $32,700
- Growth of existing $200,000 balance over 15 years at 7%
- Total at retirement: approximately $1,370,000+
Even with just 15 years, aggressive contributions with catch-up plus a generous employer match can build substantial wealth. The $200,000 existing balance nearly triples on its own, and the high annual contributions compound quickly.
Frequently Asked Questions
A widely cited guideline is to save 15% of your gross income for retirement, including any employer match. If your employer matches 3%, you'd need to contribute 12% on your own. If 15% isn't feasible right now, start with whatever you can — even 3% to 5% — and increase by 1% each year. The most important thing is to contribute at least enough to get your full employer match, since that's an immediate guaranteed return on your money.
Traditional 401(k) contributions reduce your taxable income now but are taxed when you withdraw in retirement. Roth 401(k) contributions are made with after-tax dollars but grow and are withdrawn tax-free. If you expect to be in a higher tax bracket in retirement, Roth makes sense. If you need the tax break today or expect a lower bracket later, traditional is the better choice. Many financial advisors recommend a mix of both to create tax flexibility in retirement.
Your own contributions and their earnings are always yours. Employer match funds follow the plan's vesting schedule — you might forfeit unvested portions. When you leave, you can leave the money in the old plan, roll it into your new employer's 401(k), roll it into a traditional IRA, or cash it out. Cashing out triggers income tax plus a 10% penalty if you're under 59 and a half, so rolling the funds into another retirement account is almost always the better move.
Yes, but it's generally expensive. Withdrawals before age 59 and a half typically incur a 10% early withdrawal penalty on top of regular income tax. Exceptions include hardship withdrawals (for immediate financial need), disability, certain medical expenses, and the Rule of 55, which allows penalty-free withdrawals if you leave your employer at age 55 or later. Some plans also allow loans against your balance, which avoid the penalty but must be repaid within five years.
Historically, a diversified portfolio of stocks and bonds has returned around 7% to 8% annually after inflation adjustments. Aggressive all-stock portfolios have averaged closer to 10% nominal (before inflation), while conservative bond-heavy portfolios have returned 4% to 5%. The 7% figure used as a default in this calculator is a reasonable middle-ground assumption for a balanced portfolio over long periods, though actual returns will vary year to year.
Catch-up contributions are extra amounts the IRS lets you contribute to your 401(k) once you turn 50. For 2024, the standard employee limit is $23,000, but workers aged 50 and older can add an additional $7,500, for a total of $30,500. This calculator automatically factors in catch-up contributions when your age reaches 50 during the projection period. Catch-up contributions are especially valuable for people who got a late start on retirement savings or who are now in their peak earning years and want to accelerate their savings.
The 4% rule is a widely cited guideline suggesting that you can withdraw 4% of your retirement portfolio each year and have a high probability of your money lasting at least 30 years. On a $1 million balance, that's $40,000 per year or about $3,333 per month. The rule comes from historical analysis of stock and bond returns and has held up reasonably well across various market conditions. It's a useful starting point for estimating retirement income, though your actual safe withdrawal rate may differ based on market conditions, asset allocation, and how long your retirement lasts.