401(k) Calculator

How to Use This Calculator

Enter your age, salary, and how much you're contributing to your 401(k). Add your employer's match details and hit calculate. The tool projects your balance at retirement, broken down into three pieces: your contributions, your employer's free money, and the investment returns your money earns on its own.

The most eye-opening thing you can do? Compare a 6% contribution with a 15% contribution. The difference at retirement is usually hundreds of thousands of dollars — and it doesn't shrink your paycheck nearly as much as you'd expect, thanks to the tax savings.

Here's what each field means:

Current Age is how old you are right now. The calculator uses this to figure out how many years your money has to grow before retirement.

Annual Salary is your gross pay before taxes. This is the number your contribution percentage is based on.

Current 401(k) Balance is how much you've already accumulated in your 401(k). If you're just starting, enter $0. If you've been contributing for a few years, check your most recent statement.

Contribution Type lets you enter your contribution as a percentage of salary or a flat dollar amount. Most people think in percentages because that's how payroll deductions work.

Your Contribution is the percentage of your salary (or dollar amount) you put into your 401(k) each pay period. For 2026, the IRS lets you contribute up to $24,500 per year if you're under 50 [1].

Match Rate is how much your employer contributes for every dollar you put in. A 50% match means they add 50 cents for every $1 you contribute. A 100% match means dollar-for-dollar.

Match Limit (% of Salary) is the maximum percentage of your salary that your employer will match. If the limit is 6% and you earn $75,000, your employer will match contributions on up to $4,500 of your salary. Contributing beyond that percentage still grows your retirement savings, but you won't get additional matching.

Retirement Age is when you plan to stop working and start withdrawing. The traditional age is 65-67, but you can model earlier or later retirement.

Expected Annual Return is the average yearly growth rate you expect from your investments. A diversified mix of stocks and bonds has historically returned about 7% after inflation [2]. More conservative portfolios (heavy on bonds) might return 4-5%, while aggressive portfolios (mostly stocks) might average 8-10%.

What Is a 401(k)?

A 401(k) is a retirement savings plan offered by your employer. The name comes from section 401(k) of the Internal Revenue Code — not the most exciting origin story, but the plan itself is one of the most powerful wealth-building tools available to working Americans.

Here's the basic idea: money comes out of your paycheck before you pay income taxes on it, goes into an investment account, and grows tax-free until you withdraw it in retirement. About 70 million Americans use one [3].

The three big advantages of a 401(k) are the tax break, the employer match, and the high contribution limits.

The Tax Advantage: Paying Less Now (or Later)

There are two types of 401(k) contributions, and they handle taxes differently.

Traditional 401(k)

With a traditional 401(k), your contributions come out of your paycheck before income taxes are calculated. This means every dollar you contribute reduces your taxable income today.

Here's what that looks like. Say you earn $75,000 and contribute 10% ($7,500) to a traditional 401(k). The IRS doesn't tax you on $75,000 — it taxes you on $67,500. If you're in the 22% tax bracket, that contribution saves you $1,650 in taxes this year [4].

The trade-off? When you withdraw the money in retirement, you'll pay income taxes on it then. You're essentially deferring your tax bill to the future, betting that your tax rate in retirement will be lower than it is now.

Roth 401(k)

A Roth 401(k) works in reverse. Your contributions come from after-tax dollars — no tax break today. But when you withdraw the money in retirement, it's completely tax-free. Every penny. The contributions, the employer match, the decades of investment growth — all of it comes out without a dime going to the IRS.

This is a better deal if you expect to be in a higher tax bracket in retirement, or if you believe tax rates will go up in the future.

Which One Should You Pick?

If you're early in your career and earning less than you expect to later, Roth often makes more sense. If you're in your peak earning years and paying a high tax rate, traditional usually wins. When in doubt, splitting contributions between both gives you tax flexibility in retirement.

The Employer Match: Don't Leave Free Money on the Table

This is the closest thing to free money you'll ever see. If your employer offers a 401(k) match, they're literally giving you extra compensation — but only if you contribute enough to trigger it.

How Matching Works

The most common match formula is 50% of your contributions up to 6% of your salary. Let's break that down with a $75,000 salary:

• You contribute 6% = $4,500 per year
• Your employer matches 50% of that = $2,250 per year
• Total going into your 401(k) = $6,750 per year

If you only contribute 3%, you'd get $1,125 in matching (50% of $2,250). You're leaving $1,125 on the table every single year.

Over a 30-year career with 7% returns, that $1,125 annual gap turns into roughly $106,000 in lost retirement savings. That's the real cost of not maxing your match.

The #1 Rule

At minimum, contribute enough to get the full employer match. This should be non-negotiable — it's an instant 50% or 100% return on your money, depending on your match rate. No investment in the world consistently offers that.

Contribution Limits for 2026

The IRS sets annual limits on how much you can put into your 401(k) [1]:

The total limit — combining your contributions and your employer's — is $72,000 per year [1].

The "super catch-up" provision for ages 60-63 is new, starting in 2025 under the SECURE 2.0 Act [5]. If you're in that age range, take advantage of it.

One important change for 2026: if you earned more than $150,000 in the prior year, any catch-up contributions must go into a Roth 401(k), not traditional [5].

What Happens to Your 401(k) When You Leave a Job?

You have four options:

Leave it where it is. If you have more than $7,000 in the account, most plans let you keep the money invested even after you leave. This is the do-nothing option, and it's fine if you like the plan's investment choices.

Roll it into your new employer's plan. If your new job has a 401(k), you can usually transfer the money directly. No taxes, no penalties.

Roll it into an IRA. This gives you more investment options than most employer plans. It's a popular choice. Just make sure you do a "direct rollover" (the money transfers institution-to-institution) to avoid tax consequences.

Cash it out. This is almost always a bad idea. You'll owe income taxes on the full amount plus a 10% early withdrawal penalty if you're under 59½ [6]. On a $50,000 balance, that could cost you $15,000 or more. Years of savings, gone.

A Quick Example

Meet Sarah. She's 30, earns $75,000, and has $25,000 in her 401(k). She contributes 10% of her salary, her employer matches 50% up to 6%, and she expects a 7% annual return. She plans to retire at 67.

Here's how her 401(k) breaks down over 37 years:

• Her contributions: ~$496,000
• Employer match: ~$149,000
• Investment returns: ~$1,966,000
• Total at retirement: ~$2,636,000

Look at those numbers. Sarah put in about $496,000 of her own money. Her employer added $149,000. But the investment returns — the compound growth on all that money over 37 years — generated nearly $2 million. That's four times what she contributed.

This is why starting early matters so much. Time is the engine that turns modest contributions into serious wealth.

Common 401(k) Mistakes to Avoid

Not contributing enough to get the full match. Every unmatched dollar is compensation you're declining. At minimum, hit the match threshold.

Cashing out when changing jobs. The taxes and penalties will eat 30-40% of your balance. Roll it over instead.

Not increasing contributions when you get a raise. Got a 4% raise? Bump your contribution by at least 1-2%. You won't miss money you never saw in your paycheck.

Ignoring your investment options. Many people stick with the default fund without understanding it. If your plan offers target-date funds, they automatically adjust your investment mix as you age — a solid choice for most people.

Forgetting about vesting. Your contributions are always 100% yours, but your employer's matching contributions may not be. Many plans require you to work for 3-6 years before the match is fully "vested" — meaning it becomes yours to keep even if you leave [7]. Check your plan's vesting schedule before making job change decisions.

What the Chart Shows You

The calculator chart breaks your projected balance into three color-coded pieces:

Your Contributions (blue) is the money that came directly from your paycheck over the years.

Employer Match (gold) is the free money your employer added on top of your contributions.

Returns (green) is the investment growth — the money your money earned. In the early years, this bar is small. By retirement, it dominates. That's compound interest doing its thing.

References

1. Internal Revenue Service. (2025). 401(k) Limit Increases to $24,500 for 2026. IR-2025-178.
2. Damodaran, A. (2024). Historical Returns on Stocks, Bonds and Bills: 1928-2023. NYU Stern School of Business.
3. Investment Company Institute. (2025). 401(k) Plan Asset Allocation, Account Balances, and Loan Activity.
4. Internal Revenue Service. (2025). IRS Provides Tax Inflation Adjustments for Tax Year 2026.
5. U.S. Congress. (2022). SECURE 2.0 Act of 2022. Division T of the Consolidated Appropriations Act, 2023.
6. Internal Revenue Service. (2025). Topic No. 558, Additional Tax on Early Distributions from Retirement Plans.
7. U.S. Department of Labor. (2025). What You Should Know About Your Retirement Plan.

This calculator is for educational purposes only and does not constitute financial advice. Actual investment returns vary, and past performance does not guarantee future results. Consider consulting a qualified financial advisor for personalized guidance.