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401(k) Calculator (US)

Last verified: 24 Sept 2026

Statutory baseline: Internal Revenue Service (IRS) · Contribution Limits & SECURE 2.0.

$

Gross pre-tax annual income

%

Percentage deducted each paycheck

%

e.g. 50% match (50c on the dollar)

%

Max % of salary matched by employer

%

Expected annual portfolio compound return

Years

Time horizon until retirement withdrawals start

US Jurisdiction Lock

This calculator operates strictly in US Dollars ($) reflecting US Internal Revenue Code 401(k) contribution rules.

Results

Projected 401(k) Balance
$1,345,805
Your Contributions$240,000
Employer Match (Free Money)$90,000
Total Contributed$330,000
Compound Growth / Gains$1,015,805

Assumes regular contributions and annual compounding. Not investment advice.

How 401(k) compound growth works

A 401(k) plan is an employer-sponsored retirement savings account defined under Section 401(k) of the US Internal Revenue Code. Elective employee deferrals reduce your current taxable gross income, while company matching contributions provide an immediate, guaranteed boost to your retirement savings. All funds compound tax-deferred until distribution.

Each year's account accumulation combines ongoing savings and compound market performance:

Balancet = (Balancet−1 + Cemployee + Cemployer) × (1 + r)

Cemployer = Salary × min(Contribution %, Match Cap %) × Match Rate %

  • Balancet — 401(k) balance at the end of year t
  • Cemployee — Annual employee contribution (Salary × Contribution %)
  • Cemployer — Annual employer matching contribution
  • r — Annual nominal portfolio rate of return (decimal)

Worked example: $100,000 salary over 30 years at 8% return

Consider an employee earning $100,000 annually who contributes 8% of salary with an employer match of 50% up to 6% of salary, invested for 30 years at an expected 8% annual return:

1. Annual Employee Contribution: 8% of $100,000 = $8,000/year

2. Annual Employer Match: 50% of the first 6% ($6,000) = $3,000/year

3. Combined Annual Inflow: $8,000 + $3,000 = $11,000/year

4. Cumulative Contributions over 30 Years:

  • Your direct payroll contributions: 30 × $8,000 = $240,000
  • Employer matching contributions: 30 × $3,000 = $90,000
  • Total capital contributed: $330,000

5. Compound Investment Growth: +$1,015,805

6. Final Projected 401(k) Balance: $1,345,805

The Power of Compound Growth: Over a 30-year horizon, compound returns generate $1.01M — more than triple the total deposits made by you and your employer combined.

Interpreting your 401(k) results

Capturing the Full Employer Match: Employer matching represents an immediate 50% or 100% risk-free return on your savings. Contributing less than your company's matching ceiling (6% in this example) forfeits direct compensation.

Tax-Deferred vs. After-Tax Balance: The projected balance represents gross tax-deferred assets. In a Traditional 401(k), distributions taken during retirement are taxed as ordinary income at your future tax bracket. If utilizing a Roth 401(k), qualified distributions at retirement are completely federal income tax-free.

Key assumptions and limitations

  • Flat Salary Baseline: The simulation holds salary and annual contributions constant across the tenure without modeling merit raises or inflation wage adjustments.
  • Linear Annual Return: Assumes a constant 8.0% annual rate of return. Real financial markets fluctuate, introducing sequence-of-returns risk especially during the 5–10 years immediately preceding retirement.
  • Immediate Vesting: Assumes 100% immediate vesting of all employer match funds. Some company plans utilize graded vesting schedules (e.g. 20% per year of service) or cliff vesting.
  • IRS Statutory Contribution Caps: Employee contributions cannot exceed IRS elective deferral limits ($23,000 for 2024; $23,500 for 2025; plus catch-up for age 50+).
  • Plan Fees Excluded: Does not deduct underlying mutual fund expense ratios, index tracking error, or plan administration charges.
Deciding between pre-tax and post-tax contributions?Read our in-depth analysis on Traditional vs. Roth 401(k): How to Choose Based on Tax Brackets and Retirement Horizon to evaluate marginal tax arbitrage, employer match rules, and SECURE 2.0 catch-up provisions.

Frequently asked questions

What is employer matching in a 401(k)?
Employer match is additional money contributed by your company based on your own contributions. For instance, a 50% match up to 6% of salary means that if you contribute 6% of your $100,000 salary ($6,000), your employer contributes an additional $3,000, bringing total annual contributions to $9,000.
When can I withdraw from a 401(k) without penalty?
Generally, qualified penalty-free distributions can begin at age 59½. Non-qualified withdrawals prior to 59½ are typically subject to regular income taxes plus an additional 10% early withdrawal tax penalty, barring specific statutory exceptions.
What is the annual employee contribution limit for a 401(k)?
For 2024–2026, the IRS employee elective deferral limit is $23,000 to $23,500 per year, with an additional catch-up contribution permitted for workers aged 50 and older.
What is the difference between Traditional and Roth 401(k)?
A Traditional 401(k) is funded with pre-tax dollars, lowering your taxable income today, and withdrawals in retirement are taxed as ordinary income. A Roth 401(k) is funded with after-tax dollars, but qualified withdrawals in retirement are completely tax-free.
What average annual return rate is realistic for a 401(k)?
Historically, broad US equity indices like the S&P 500 have generated long-term nominal annualized returns around 9% to 10% (around 7% real after inflation). Diversified retirement portfolios containing bonds typically project between 6% and 8% p.a.

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Projected 401(k) Balance

$1,345,805