401K Calculator

What This Calculator Does

You sit down to review your benefits package. The 401(k) section mentions employer matching, vesting schedules, and contribution limits. The numbers blur together. How much will you actually have when you retire?

A 401(k) is an employer-sponsored retirement savings plan that lets you invest pre-tax dollars for retirement. This calculator projects your 401(k) balance at retirement by combining your current balance, ongoing contributions, employer matching, and compound investment growth. It shows you exactly how much free money you may be leaving on the table by not maximizing your employer match.

According to Vanguard's most recent How America Saves data, the average promised employer match is 4.6% of pay. Yet a significant share of workers do not contribute enough to capture it. A 2026 analysis found that the average American leaves $2,954 on the table every year by skipping the employer match. Over a 35-year career, that compounds into hundreds of thousands in lost retirement savings.

Inputs Required

• Current Age and Retirement Age: Determines how many years your money compounds
• Current 401(k) Balance: What you already have invested
• Annual Salary: Used to calculate dollar amounts from percentages
• Your Contribution Percentage: The portion of your salary you contribute each paycheck
• Employer Match Percentage: How much your employer matches per dollar contributed
• Employer Match Limit: The cap on your salary percentage that the employer will match
• Expected Annual Return: Your projected average investment return

Outputs Provided

• Projected Balance: Your estimated 401(k) value at retirement
• Your Contributions: Total amount you personally contributed
• Employer Match: Total free money received from your employer
• Investment Growth: Returns generated by compound interest on all contributions

How the Calculation Works

The calculator compounds monthly. Each month, your balance earns a return equal to the annual rate divided by 12. Your employee contribution is added (your salary multiplied by your contribution percentage divided by 12). The employer match is also added, capped at the match limit percentage of your salary.

The employer match formula means: if your employer matches 50% of your contributions up to 6% of salary, and you contribute 6%, your employer adds 3% of your salary (50% of 6%). If you only contribute 4%, your employer adds 2% (50% of 4%). The most common formula on Fidelity's platform in 2026 pays 100% on the first 3% of contributions and 50% on the next 2%, effectively adding 4% of salary when you contribute 5%.

How to Use the Calculator

1. Enter your current and retirement ages
2. Input your current 401(k) balance (check your last statement)
3. Enter your annual salary before taxes
4. Set your contribution percentage (check your pay stub if unsure)
5. Enter your employer match details from your benefits summary
6. Set your expected return rate and view your projected balance

For the expected return rate, a diversified stock portfolio has historically averaged around 7% annually after inflation. If your 401(k) is heavily in bonds or stable value funds, use a lower rate like 4% or 5%. You can also model different scenarios by adjusting the return rate up and down to see the range of possible outcomes. For a broader view of your retirement picture, pair this with our Retirement Calculator to see how your 401(k) fits into your overall savings plan.

Example Calculations

Example 1: The 30-Year-Old Software Engineer

Marcus is a 32-year-old software engineer in Austin, Texas. He earns $95,000 per year and has $28,000 already in his 401(k). He contributes 6% of his salary, and his employer matches 100% up to 4% of salary. He expects a 7% annual return and plans to retire at 65.

• Annual employee contribution: $5,700
• Annual employer match: $3,800 (100% of 4% of salary)
• Projected balance at 65: approximately $1,240,000
• Total employer contributions over 33 years: approximately $125,000 in free matching

That $125,000 in employer contributions grows to roughly $430,000 through compound interest by retirement. The true value of the match is more than triple what the employer actually put in.

Example 2: The Late Starter at 45

Diane is 45 and just started taking retirement savings seriously. She has $15,000 saved, earns $72,000, and contributes 8%. Her employer matches 50% up to 6%. She uses a conservative 6% return and plans to retire at 67.

• Annual employee contribution: $5,760
• Annual employer match: $2,160 (50% of 6% of salary)
• Projected balance at 67: approximately $410,000
• Total employer contributions over 22 years: approximately $47,500

Even starting late, the combination of consistent contributions and employer matching builds a meaningful nest egg. If Diane uses the SECURE 2.0 catch-up provision at age 50, she can add an extra $8,000 per year on top of the 2026 limit of $24,500, accelerating her growth further. You can model this additional savings in our Roth IRA Calculator to compare tax-free versus tax-deferred growth.

Real World Scenarios

The Half-Match Problem

Tom contributes only 3% of his salary when his employer matches 50% up to 6%. He is leaving half the employer match uncaptured. On a $75,000 salary, that is $1,125 per year in free money he does not receive. By increasing his contribution to 6%, he adds thousands in free employer money each year. The out-of-pocket cost is lower than it appears because contributions are pre-tax, so his taxable income drops and his take-home pay decreases by less than the contribution amount.

The Auto-Escalation Strategy

Sandra starts at 5% and enrolls in her plan's auto-escalation feature, which increases her contribution by 1% each year after raises. Over 30 years, that incremental increase compounds into a meaningfully larger balance. If she eventually reaches 15% and her salary grows from $70,000 to $110,000, the calculator shows a projected balance roughly 60% higher than if she had stayed at 5% the entire time. Many plans now offer auto-escalation by default under SECURE 2.0 provisions.

Comparing Job Offers with Different Match Structures

When comparing two job offers, the 401(k) match structure can swing the total compensation by thousands per year. A 100% match up to 3% sounds smaller than a 50% match up to 6%, but if you only contribute 3%, the first offer gives you 3% of salary in free money while the second gives you only 1.5%. If you contribute 6% or more, the second offer gives you 3% total, matching the first. Run both scenarios through the calculator with your expected contribution rate and salary to see the real difference over a 5-year or 10-year horizon.

2026 Contribution Limits and SECURE 2.0 Changes

The IRS raised the 401(k) employee contribution limit to $24,500 for 2026, up from $23,500 in 2025. If you are 50 or older, you can add a catch-up contribution of $8,000, bringing your personal maximum to $32,500. Under the SECURE 2.0 Act, workers aged 60 through 63 qualify for a super catch-up of $11,250, allowing them to contribute up to $35,750 in a single year.

Starting in 2026, SECURE 2.0 also requires high earners (those who earned over $150,000 in the prior year) to make their catch-up contributions on a Roth basis. This means those contributions are after-tax but withdrawals in retirement are tax-free. You can explore how Roth contributions grow differently using our Roth IRA Calculator.

Employer contributions do not count toward the employee limit but do count toward the combined employer-employee limit. For the full details on current limits, refer to the IRS 401(k) contribution limits page.

Common Mistakes to Avoid

• Not capturing the full employer match: Always contribute at least enough to get your full employer match before directing money elsewhere. The average worker leaves $2,954 per year uncaptured.
• Cashing out when changing jobs: Early withdrawals trigger income taxes and a 10% penalty, erasing years of growth. Roll the balance into your new employer's plan or an IRA instead.
• Ignoring investment allocation: The return rate in this calculator assumes a chosen portfolio. Leaving money in a default money market fund or stable value fund dramatically reduces long-term growth. Check your allocation annually.
• Not increasing contributions with raises: Keep your lifestyle the same after a raise and direct the extra income to your 401(k). Auto-escalation features make this effortless.
• Forgetting about vesting schedules: Some employers require 3 to 6 years of service before employer match funds are fully yours. If you change jobs before vesting, you may lose the match entirely.

Limitations of This Calculator

This tool provides an estimate, not a guarantee. It does not account for salary growth over time, inflation, changes in contribution rates, or investment fees. Real 401(k) returns fluctuate year to year and are never a smooth fixed rate. The calculator also does not model Roth 401(k) contributions, loans, or early withdrawals. For a complete retirement plan, consider working with a fee-only financial advisor. This calculator does not replace professional tax or financial advice.

Authoritative Research and Resources

• IRS 401(k) Contribution Limits - The official IRS page with current year limits, catch-up rules, and combined employer-employee caps. Use this to verify the maximum you can contribute.
• IRS Announcement: 401(k) Limit Increases to $24,500 for 2026 - The official IRS press release announcing 2026 cost-of-living adjustments for retirement plans.
• SECURE 2.0 Catch-Up Contribution Rules - A detailed breakdown of the final SECURE 2.0 regulations, including the Roth catch-up requirement for high earners starting in 2026.

For a broader view of your retirement income needs, try our Retirement Calculator or Investment Calculator to model additional savings outside your 401(k).