A 401(k) calculator projects how your employer-sponsored retirement account grows over your career, including the employer match. This calculator estimates 401(k) growth using salary, employee contribution percentage, employer match percentage, expected return, and years to retirement, expressed as a projected account balance, total contributions split between you and your employer, and a 4%-rule monthly withdrawal.
The 2026 IRS employee deferral limit is $23,500 under age 50 and $31,000 for savers 50 or older with the catch-up contribution (per the IRS, 2025); the combined employee-plus-employer cap is $70,000 under 50 and $77,500 at 50-plus. Roughly 51 percent of US private-industry workers participate in an employer-sponsored defined-contribution plan (per the Bureau of Labor Statistics National Compensation Survey, 2024).
The employer match is the highest-return investment most employees will ever access. A typical 50 percent match on the first 6 percent of salary equals a 3 percent effective contribution; in return-on- contribution terms, the day you contribute the qualifying 6 percent, your employer adds 50 cents to every dollar, an instant 50 percent return that no market portfolio can match over any time horizon. Three modeling caveats: salary is held constant (real careers grow roughly 3 percent annually), contribution percentages are held constant, and IRS dollar limits are not enforced inside the percentage model, so high earners may exceed the cap on paper.
Key takeaway
The full employer match is the highest-return investment most people have access to. A 50% match on the first 6% of salary means the moment you contribute that 6%, you've earned an instant 50% return on those dollars, uncatchable by any market portfolio over any time horizon. Always contribute at least enough to capture the full match before redirecting savings elsewhere (Roth IRA, taxable brokerage, paying down debt). Leaving match on the table is leaving compensation on the table.
How it's calculated
Combined annual contribution = salary × (your_pct + match_pct) / 100, converted to a monthly contribution by dividing by 12. The future-value-of-annuity formula with monthly compounding produces:
FV = P × (1 + i)^n + (C/12) × ((1 + i)^n − 1) / i
Where:
- P is your current 401(k) balance
- C is the annual contribution (yours + employer's)
- i is the monthly rate (annual rate / 12)
- n is months to retirement
A few simplifications worth flagging: salary is held constant (in reality it grows ~3%/year); contribution percentages are held constant (most people raise them as they earn more); and IRS contribution limits aren't enforced (the 2026 limit is $23,500 employee + matching). For high earners, real-world contributions hit a hard ceiling that this calculator's percentage model doesn't capture.
Source: Future-value-of-annuity with monthly compounding plus employer match modeled as added contribution
Examples
Mid-career: 35yo, $75K salary, 6% + 3% match, 30 years
- Current 401(k) balance $25,000
- Annual salary $75,000
- Your contribution 6%
- Employer match 3%
- Current age 35
- Retirement age 65
- Expected annual return 7%
A 35-year-old earning $75K with $25K saved, contributing 6% with a 3% employer match for 30 years at 7%, retires with about $889K. Your contributions: $135,000. Employer's: $67,500. Investment growth: ~$686,000. The employer match alone added $67,500 of principal that compounded into a much larger share of the final balance, illustrating why match is the highest-return investment most people have access to.
Aggressive saver: $100K salary, 15% + 4% match, 25 years
- Current 401(k) balance $50,000
- Annual salary $100,000
- Your contribution 15%
- Employer match 4%
- Current age 40
- Retirement age 65
- Expected annual return 7%
A 40-year-old earning $100K with $50K saved, contributing 15% with a 4% employer match (19% combined) for 25 years at 7% retires with about $1.57M, supporting ~$5,230/month under the 4% rule. Aggressive contribution rates compress the time disadvantage of starting later; the trade-off is higher current-period saving rate and tighter cash flow during peak earning years.
Frequently asked questions
What is the 401(k) contribution limit for 2026?
For 2026, the IRS employee contribution limit is $23,500 if you're under 50 and $31,000 if you're 50 or older (the catch-up contribution is $7,500 in 2026). The combined limit (employee + employer) is $70,000 under 50 and $77,500 at 50+. These limits typically increase by $500–$1,000 each year for inflation, verify the current year on the IRS retirement plan limits page before maxing out. The percentage-based model in this calculator doesn't enforce these caps; high contribution rates at high salaries may exceed them.
Should I contribute to a 401(k) or a Roth IRA first?
Always capture the full 401(k) employer match first, that's free money. After the match, the choice depends on your current vs. expected retirement tax bracket. Roth IRA (Pay tax now, withdraw tax-free): better if you expect to be in the same or higher tax bracket in retirement (most younger workers). Traditional 401(k) (Pre-tax now, taxed on withdrawal): better if you expect a lower retirement tax bracket (peak earners). Many people contribute to both, capturing the match in the 401(k) and adding a Roth IRA on top up to its annual limit ($7,000 in 2026).
What happens to my 401(k) when I leave my employer?
You have four options: (1) leave it in the old plan (sometimes possible above a balance threshold, often $5,000+); (2) roll over to your new employer's 401(k) if they accept rollovers; (3) roll over to a traditional IRA, which usually has lower fees and more investment options; (4) cash out, almost always the wrong choice, since pre-59½ withdrawals trigger income tax plus a 10% penalty per IRS early-withdrawal rules. Rolling to an IRA is the most common move; it preserves the tax-deferred status and gives you full control over investment choices.
How does vesting work?
Vesting refers to ownership of employer-contributed funds; your own contributions are always 100% yours immediately. Common vesting schedules: immediate (0% match forfeited if you leave), cliff (e.g., 100% vested after 3 years; 0% before), or graded (e.g., 20% per year over 5 years). Check your plan's Summary Plan Description for the schedule. If you're considering a job change, the unvested portion of your match is real money on the table, sometimes worth waiting a few months to vest.