MathIsimple
Finance · 2025-2026

401k Calculator

Calculate your 401k retirement savings with employer match and compound growth projections

100% FreeStep-by-Step Solutions
401k Calculator
Enter your current balance, contributions, employer match, and expected return
Enter to calculate, Esc to clear
Try These Examples
Click on any example to automatically fill the calculator
Early Saver

5,000current,5,000 current,6,000 annual, 50% match, 7% return, 40 years

currentBalance: 5000
annualContribution: 6000
employerMatchPercent: 50
annualReturn: 7
years: 40
Mid-Career

100,000current,100,000 current,15,000 annual, 100% match up to 6%, 7% return, 20 years

currentBalance: 100000
annualContribution: 15000
employerMatchPercent: 50
annualReturn: 7
years: 20
Late Starter

20,000current,20,000 current,20,000 annual, 50% match, 6% return, 15 years

currentBalance: 20000
annualContribution: 20000
employerMatchPercent: 50
annualReturn: 6
years: 15
Max Contributor

50,000current,50,000 current,23,000 annual, 100% match up to 6% ($5,000), 8% return, 25 years

currentBalance: 50000
annualContribution: 23000
employerMatchPercent: 25
annualReturn: 8
years: 25
2024-2025 Contribution Limits
IRS annual limits for 401k plans
Under Age 50
$23,000
2024 limit
Age 50+ (Catch-up)
$30,500
$23,000 + $7,500
2025 Update: The limit increases to $23,500 ($31,000 with catch-up). Ages 60-63 get a super catch-up of $11,250 extra!
Traditional vs Roth 401k
Choose the right type for your situation
FeatureTraditionalRoth
Tax on ContributionsPre-tax ✓After-tax
Tax on WithdrawalsTaxedTax-free ✓
Best ForHigher tax nowLower tax now
RMDs Required?Yes (age 73)No
Pro tip: Many advisors recommend having both for tax diversification in retirement.
The Power of Compound Growth
See how time multiplies your money
Starting with $500/month at 7% annual return:

Projection model: FV=P(1+r)n+PMT(1+r)n1rFV = P(1+r)^n + PMT \cdot \frac{(1+r)^n - 1}{r}

10 Years
$86,000
20 Years
$260,000
30 Years
$610,000
Total contributions: $180,000 over 30 years. Growth: $430,000+ from compound interest!
About 401k Plans

A 401k is an employer-sponsored retirement savings plan with significant tax advantages:

  • Pre-tax contributions reduce your current taxable income
  • Employer matching is essentially "free money"
  • Tax-deferred growth until withdrawal in retirement
  • Early withdrawal (before 59½) incurs 10% penalty + taxes
401(k) Planning Guide for 2026 Contributions
Quick answer: if you contribute enough to capture your full employer match, increase your savings rate by 1% each year, and keep a diversified allocation, your 401(k) typically becomes the core of a long-term retirement plan. This calculator lets you test how contribution amount, match rules, and return assumptions change your projected retirement balance. Use the result to compare realistic scenarios such as job changes, lower return environments, or delayed retirement. For most savers, the highest-impact move is maximizing tax-advantaged contributions before adding taxable brokerage savings.

Your projected balance combines three engines: your current account value, new annual contributions, and compounding investment growth. In a fixed annual projection, the model is:

A=P(1+r)n+PMT(1+r)n1rA = P(1+r)^n + PMT\cdot\frac{(1+r)^n-1}{r}

Here, PP is your current balance, rr is expected annual return, nnis years to retirement, and PMTPMT is your yearly contribution including employer match. The formula does not predict market timing, but it's a useful planning baseline for contribution strategy, withdrawal sequencing, and target retirement age.

Example: assume you already saved $40,000, contribute $9,000 yearly, receive a $3,000 employer match, and model a 7% long-term return. Over 25 years, your personal contributions plus match total $300,000, while compounding can add several hundred thousand more. Run this same case with 5%, 6%, and 7% return assumptions to build a range instead of a single-point forecast. Planning with a range helps you avoid overconfidence and keeps your retirement timeline resilient when markets underperform.

Common mistake #1 is ignoring vesting. Some employer match dollars are not immediately yours, so a job change can reduce the match benefit. Common mistake #2 is contributing below the match threshold; that leaves guaranteed compensation on the table. Common mistake #3 is using an unrealistically high expected return and then under-saving. A practical workflow is: capture full match, raise contribution annually, rebalance once or twice per year, and review assumptions when salary or expenses change.

Use cases where this calculator is especially useful: comparing Traditional vs Roth contribution split, testing whether an annual bonus should go to debt payoff or retirement, and evaluating the impact of retiring 3 to 5 years earlier. If you're age 50+, include catch-up contributions in your annual input. If you're evaluating a new job offer, run side-by-side scenarios with different match percentages, vesting schedules, and salary growth expectations.

This tool is educational and should support, not replace, personalized planning. Tax bracket changes, Social Security timing, pension income, and required minimum distribution rules can materially change your retirement cash flow. Confirm current contribution limits and withdrawal rules with official IRS publications and your plan administrator before making final decisions.

Frequently Asked Questions

Contribute at least enough to get the full employer match (typically 3-6% of salary). Ideal: max out the IRS limit ($23,000 in 2024, or $30,500 if 50+). If you can't max out, contribute at least 10-15% of gross income.
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401k Calculator 2025-2026 - Calculate 401k Retirement Savings | MathIsimple