Free, open-source 401(k) retirement calculator with employer matching and 2026 contribution limits.
Project your retirement savings with employer match, catch-up contributions, the new super catch-up for ages 60-63, and a complete year-by-year breakdown.
Use the 401(k) Calculator on BullRun Forever Tools — includes interactive charts, scenario comparison, CSV export, and dark mode.
- 2026 401(k) contribution limits ($24,500 / $32,000 / $35,750)
- Employer matching calculations (configurable match % and cap)
- Catch-up contributions for ages 50+ ($7,500)
- NEW: Super catch-up contributions for ages 60-63 ($11,250)
- Year-by-year growth breakdown with employer match tracking
- Tax savings estimation from pre-tax contributions
- 30-year extended projection
- Zero dependencies — pure JavaScript math
| Age Group | Employee Limit | Catch-Up | Total |
|---|---|---|---|
| Under 50 | $24,500 | — | $24,500 |
| 50-59 | $24,500 | $7,500 | $32,000 |
| 60-63 | $24,500 | $11,250 | $35,750 |
| 64+ | $24,500 | $7,500 | $32,000 |
The SECURE 2.0 Act introduced the super catch-up provision for ages 60-63, allowing an additional $11,250 on top of the base limit.
Total Annual Addition Limit (employee + employer): $71,000
npm install
npm run devOpen http://localhost:5173 to use the calculator locally.
The calculator models year-by-year 401(k) growth including employee contributions, employer matching, and compound returns:
For each year from current age to retirement age:
1. Determine contribution limit based on age
2. Calculate employee contribution (salary × contribution%, capped at limit)
3. Calculate employer match (employee contribution × match%, capped at matchable salary)
4. Add both contributions to balance
5. Apply annual return: growth = balance × rate
6. End-of-year balance = balance + growth
matchableAmount = annualSalary × (matchCap / 100)
employeeContributionForMatch = min(employeeContribution, matchableAmount)
employerMatch = employeeContributionForMatch × (matchPercent / 100)
Example: Salary $75,000, employer matches 50% up to 6% of salary:
Matchable Amount: $75,000 × 6% = $4,500
If employee contributes $4,500+:
Employer Match: $4,500 × 50% = $2,250/year (FREE money!)
Inputs:
- Current Age: 30, Retirement Age: 65
- Current Balance: $10,000
- Annual Salary: $75,000
- Contribution: 15% ($11,250/year)
- Employer Match: 50% up to 6%
- Expected Return: 8%
Year 1:
Employee Contribution: $11,250 (under $24,500 limit)
Employer Match: min($11,250, $4,500) × 50% = $2,250
Total Added: $13,500
Starting: $10,000 + $13,500 = $23,500
Growth: $23,500 × 8% = $1,880
Ending Balance: $25,380
After 35 years:
Total Value: ~$2,847,000
Your Contributions: ~$404,250
Employer Match: ~$78,750
Investment Earnings: ~$2,364,000
Est. Tax Savings: ~$97,020 (at 24% bracket)
| Calculation | Formula |
|---|---|
| Employee Contribution | min(salary × contributionPct, ageLimit) |
| Employer Match | min(employeeContrib, salary × matchCap) × matchPct |
| Annual Growth | balance × (annualReturn / 100) |
| Tax Savings | totalEmployeeContributions × marginalTaxRate |
| Total Earnings | finalValue - employeeContributed - employerContributed |
| Contribution Limit | Age-based: <50: $24,500 / 50-59: $32,000 / 60-63: $35,750 / 64+: $32,000 |
import { calculate401k } from './src/calculator.js';
const result = calculate401k({
currentAge: 30,
retirementAge: 65,
currentBalance: 10000,
annualSalary: 75000,
contributionPercent: 15,
annualReturn: 8,
employerMatchPercent: 50,
employerMatchCap: 6
});
console.log(result.totalValue); // ~$2,847,000
console.log(result.totalEmployerContributed); // ~$78,750
console.log(result.estimatedTaxSavings); // ~$97,020
console.log(result.yearlyBreakdown); // Array of yearly data{
totalValue: number, // Final 401(k) balance at retirement
totalEmployeeContributed: number, // Sum of your contributions
totalEmployerContributed: number, // Sum of employer match contributions
totalContributions: number, // Employee + employer total
totalEarnings: number, // Investment growth
returnOnInvestment: number, // ROI percentage
estimatedTaxSavings: number, // Tax savings from pre-tax contributions
years: number, // Years until retirement
yearlyBreakdown: [
{
year: number,
age: number,
startingBalance: number,
employeeContribution: number,
employerMatch: number,
totalContribution: number,
contributionLimit: number,
growth: number,
endingBalance: number,
totalEmployeeContributed: number,
totalEmployerContributed: number,
totalEarnings: number
}
],
thirtyYearProjection: { // Extended projection (if applicable)
totalValue: number,
totalEmployeeContributed: number,
totalEmployerContributed: number,
totalEarnings: number
}
}The 401(k) is the most widely used retirement vehicle in America:
- 70+ million Americans actively contribute (Investment Company Institute)
- Employer matching — an instant 50-100% return on your contributions
- Tax-deferred growth — investments compound without annual tax drag
- Higher limits — $24,500 vs. $7,000 for IRAs
- Automatic payroll deductions — set it and forget it
- Average employer match: 4.7% of salary (Vanguard's How America Saves 2025)
An employee earning $60,000 who skips the match forfeits $2,820/year in free money.
| Feature | Traditional 401(k) | Roth 401(k) |
|---|---|---|
| Contributions | Pre-tax (reduces taxable income) | After-tax |
| Withdrawals | Taxed as ordinary income | Tax-free |
| Best if | Lower tax bracket in retirement | Higher tax bracket in retirement |
| RMDs | Required at age 73 | Required at 73 (can roll to Roth IRA) |
What are the 2026 401(k) contribution limits? $24,500 under 50, $32,000 for ages 50+, and $35,750 for ages 60-63 (super catch-up via SECURE 2.0 Act).
How does employer matching work? Your employer contributes based on your contributions. Common: 50% match up to 6% of salary. Always contribute enough to get the full match — it's free money.
What happens to my 401(k) if I change jobs? You can leave it, roll it to your new employer's plan, roll it into an IRA, or cash out (not recommended — 10% penalty + taxes).
How much should I contribute? Financial experts recommend 10-15% of gross income for retirement. At minimum, contribute enough for the full employer match.
This calculator is part of the BullRun Forever Toolkit — 16 free financial calculators including:
- Roth IRA Calculator — Tax-free retirement growth
- Investment Calculator — Compound interest projections
- Freedom Number Calculator — FIRE number & 4% rule
- Debt Strategy Planner — Snowball vs. avalanche
- Budget Planner — Personalized budgeting
MIT License — use freely in your own projects.
This calculator is for educational and informational purposes only. It is not financial, tax, or investment advice. Consult a qualified financial advisor for personalized recommendations. Tax laws and contribution limits may change.
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