401k Calculator

Q: How much should I contribute to my 401k?

Financial advisors generally recommend contributing at least enough to get your full employer match, since that is essentially free money. Beyond that, aim for 10-15% of your gross salary if possible. The IRS allows up to $23,500 in employee contributions for 2025, with an additional $7,500 catch-up contribution if you are 50 or older.

Q: What is the 4% rule for retirement withdrawals?

The 4% rule is a guideline that says you can withdraw 4% of your retirement savings in your first year of retirement, then adjust for inflation each year after. This approach is designed to make your money last roughly 30 years. For example, a $1,000,000 401k balance would provide about $40,000 per year or $3,333 per month.

Q: Should I choose a traditional 401k or Roth 401k?

A traditional 401k reduces your taxable income now, and you pay taxes when you withdraw in retirement. A Roth 401k uses after-tax dollars, but withdrawals in retirement are tax-free. If you expect to be in a higher tax bracket in retirement, a Roth may be better. If you expect a lower bracket, traditional is usually the better choice.

Q: How does compound interest affect my 401k?

Compound interest means your investment earnings generate their own earnings over time. In a 401k, this effect is powerful because of the long time horizon. Someone who starts contributing $500 per month at age 25 with a 7% return will have significantly more at 65 than someone who starts the same contributions at 35, even though the difference in total contributions is only 10 years' worth.

Estimate how much your 401k will be worth at retirement. Enter your salary, contribution rate, employer match, and expected return to see your projected balance, total contributions, and estimated monthly retirement income.

Current Age

Retirement Age

Current 401k Balance ($)

Annual Salary ($)

Your Contribution (%)

Employer Match (%)

Match Limit (%)

Expected Annual Return (%)

Annual Salary Increase (%) — optional

How to use this calculator

Enter your current age and the age you plan to retire.
Input your current 401k balance (enter 0 if you are just starting).
Enter your annual salary and the percentage you contribute each paycheck.
Add your employer's match percentage and the salary limit they match up to.
Set your expected annual investment return (7% is a common historical average).
Optionally enter an annual salary increase to model raises over time.

How it works

The calculator simulates your 401k growth year by year from your current age to retirement. Each month, your contribution and employer match are added to the balance, and the entire balance grows at your expected rate of return. Salary increases are applied annually, which means your contributions and employer match grow over time too. The final monthly retirement income is estimated using the 4% rule — withdrawing 4% of your total balance per year, divided by 12.

What Is a 401k Calculator?

A 401k calculator is a retirement planning tool that projects how much money you will have in your employer-sponsored 401k plan by the time you retire. It factors in your current savings, ongoing contributions, employer matching, investment returns, and salary growth to give you a realistic picture of your retirement nest egg.

The power of a 401k comes from three sources working together: your contributions, your employer's matching contributions, and compound investment growth over decades. Even small changes to your contribution rate can have an enormous impact over 20 or 30 years. For example, increasing your contribution from 6% to 10% of a $75,000 salary adds just $250 per month out of pocket, but over 35 years at a 7% return, that difference can grow to over $400,000 in additional retirement savings.

Many workers leave free money on the table by not contributing enough to capture their full employer match. If your employer matches 50% of contributions up to 6% of your salary, you need to contribute at least 6% to get the maximum benefit. Anything less means you are giving up guaranteed, tax-advantaged returns that no investment can replicate.

This calculator also accounts for salary increases over time, which is important because most people earn more as they advance in their careers. A 3% annual raise compounds on itself, and since your 401k contributions are a percentage of your salary, your contributions naturally increase each year too. This accelerating contribution effect is one reason why starting early is so valuable — you capture more years of both compound growth and rising contributions.

Understanding Employer 401k Matching

Employer matching is one of the most valuable benefits in any compensation package. The most common match formula is a percentage of your contribution, up to a certain limit of your salary. For example, "50% match on the first 6%" means if you contribute 6% of your salary, your employer adds an amount equal to 3% of your salary.

Some employers offer a dollar-for-dollar match (100%) up to a lower limit like 3% or 4%. Others offer more complex tiered structures. Regardless of the formula, the principle is the same: the employer match is an immediate, risk-free return on your money. A 50% match is an instant 50% return before any market gains.

Keep in mind that employer contributions may be subject to a vesting schedule. This means you might need to work at the company for a certain number of years before you fully own the matched funds. Common vesting schedules range from immediate vesting to 6-year graded vesting. Check with your HR department to understand your specific plan.

Frequently Asked Questions

How much should I contribute to my 401k?

At a minimum, contribute enough to get your full employer match — anything less is leaving free money on the table. Financial advisors generally recommend saving 10-15% of your gross income for retirement, including the employer match. The IRS allows up to $23,500 in employee 401k contributions for 2025, with an additional $7,500 catch-up contribution if you are 50 or older.

What is an employer 401k match?

An employer match means your company contributes money to your 401k based on how much you contribute. A typical formula is a 50% match on the first 6% of your salary. So if you earn $80,000 and contribute 6% ($4,800 per year), your employer adds $2,400. That is an instant 50% return on your contributed dollars.

What is the 4% rule for retirement withdrawals?

The 4% rule is a widely used guideline suggesting you can safely withdraw 4% of your retirement portfolio in the first year of retirement, then adjust that amount for inflation each subsequent year. This strategy is designed to make your savings last approximately 30 years. A $1,000,000 balance would provide about $40,000 per year, or roughly $3,333 per month.

Should I choose a traditional 401k or Roth 401k?

With a traditional 401k, your contributions are pre-tax, lowering your taxable income now, but you pay income tax on withdrawals in retirement. With a Roth 401k, you contribute after-tax dollars, but withdrawals in retirement are completely tax-free. If you expect to be in a higher tax bracket in retirement, a Roth 401k may save you more in the long run. If you expect a lower bracket, traditional is usually the better choice.

How does compound interest affect my 401k?

Compound interest means your investment returns generate their own returns over time. In a 401k with a long time horizon, this effect is dramatic. Someone contributing $500 per month starting at age 25 with a 7% average annual return would have about $1.2 million by age 65. Starting the same contributions at age 35 would yield only about $567,000 — roughly half as much, even though the total contribution difference is only $60,000.

Example Calculation

Let's say you are 30 years old, plan to retire at 65, and currently have $25,000 in your 401k. You earn $75,000 per year, contribute 10% of your salary, your employer matches 50% up to 6% of your salary, and you expect a 7% annual return with 3% salary increases.

Your monthly contribution: $625 (10% of $75,000 / 12)
Employer monthly match: $187.50 (50% of 6% of $75,000 / 12)
Combined monthly addition: $812.50 (growing each year with raises)

After 35 years of contributions and compound growth:

Estimated total balance: approximately $1,800,000
Your total contributions: approximately $475,000
Employer total match: approximately $142,000
Investment growth: approximately $1,183,000
Monthly retirement income (4% rule): approximately $6,000

Notice that investment growth makes up the largest portion of the final balance. That is the power of compound returns over a multi-decade time horizon. Even the employer match, while modest on a monthly basis, adds up to over $142,000 in this scenario.