401(k) Retirement Calculator (with Employer Match & Compounding)

A 401(k) is a payroll-deducted, tax-advantaged retirement account, and the two biggest levers you actually control are how much of your salary you defer and whether you are capturing the full employer match on offer. This calculator models both explicitly rather than collapsing them into a single "contribution rate" number, because the employer match is frequently described as the closest thing to a guaranteed return an investor will ever see: money that shows up in your account the moment you contribute, independent of market performance.

The elective deferral limit modeled here is $23,500, the annual cap on how much of your own salary you can direct into a 401(k) before employer contributions are even considered. This limit is set by the IRS and adjusted periodically for inflation under Internal Revenue Code Section 402(g); it applies to your own payroll deferrals only and does not cap what your employer can contribute on top through matching. Employer matching itself is not standardized. This calculator uses the two variables that describe the overwhelming majority of real-world match formulas: a match percentage (how many cents your employer contributes per dollar you defer) and a match cap (the percentage of your salary up to which that match applies), which together reproduce common formulas like "50% match up to 6% of salary," the exact structure used in this calculator's baseline scenario.

Compounding is the third lever, and the one most 401(k) participants underweight psychologically because its effect is invisible year to year and enormous over a career. This calculator runs a year-by-year simulation from your current age to your target retirement age, applying your expected annual return to the account balance before adding that year's combined employee and employer contributions, which lets you see exactly how much of your eventual balance came from your own paycheck, how much came from your employer's match, and how much came from investment growth compounding on both.

Step 1: Annual contribution amounts. Employee contribution is your salary times your contribution percentage, capped at the $23,500 statutory elective deferral limit. Employer match applies only to salary up to the stated match cap:

$$\text{Employee Contribution} = \min(\$23{,}500,\ \text{Salary} \times \text{Contribution \%})$$ $$\text{Employer Match} = \min(\text{Salary} \times \text{Match Cap \%},\ \text{Salary}) \times \text{Match Rate \%}$$

Step 2: Year-by-year compounding. For each year from your current age to your retirement age, investment growth is applied to the existing balance first, then that year's total contribution (employee plus employer) is added:

$$\text{Balance}_{t} = \text{Balance}_{t-1} \times (1 + r) + \text{Employee Contribution} + \text{Employer Match}$$

Step 3: Decompose the final balance. The calculator separately tracks cumulative employee contributions, cumulative employer match, and the residual, which is pure compound investment growth:

$$\text{Compound Growth} = \text{Final Balance} - (\text{Total Employee Contributions} + \text{Total Employer Match})$$

Using this calculator's baseline inputs: a 30-year-old earning $95,000 annually with a $45,000 current balance, contributing 10% of salary, an employer match of 50% up to 6% of salary, a 7.5% expected annual return, retiring at 65 (35 years of growth).

1. Annual employee contribution: $95,000 × 10% = $9,500 (well under the $23,500 cap)
2. Salary matched by employer: $95,000 × 6% = $5,700
3. Annual employer match: $5,700 × 50% = $2,850
4. Total annual contribution: $9,500 + $2,850 = $12,350
5. Year 1 growth: $45,000 × 7.5% = $3,375; balance becomes $45,000 + $3,375 + $12,350 = $60,725
6. That same process repeats for 35 years, with growth compounding on an ever-larger base as contributions accumulate.
7. Final projected balance at age 65: $2,470,606.50
8. Total out-of-pocket employee contributions over 35 years: $377,500
9. Total employer match received over 35 years: $99,750
10. Total compound investment growth: $2,470,606.50 − ($377,500 + $99,750) = $1,993,356.50

Notice that compound growth ($1,993,356.50) is more than five times the total amount ever contributed out of pocket ($377,500). That gap is the entire argument for starting early: the same $9,500 annual contribution made at age 55 instead of age 30 would have only a decade to compound instead of 35 years, and would produce a dramatically smaller final balance despite identical contribution behavior.

• Catch-up contributions for savers age 50 and older. The IRS allows an additional catch-up deferral on top of the standard elective deferral limit for participants 50+, with an enhanced catch-up amount for ages 60-63 under SECURE 2.0. This calculator applies a flat $23,500 cap regardless of age.
• Salary growth over time. Contributions are calculated as a fixed percentage of your current salary held constant for the entire projection; real salaries typically rise with promotions and inflation, which would increase both employee contributions and employer match in later years.
• Investment fees and expense ratios. The stated annual return is treated as a net figure; actual fund expense ratios, plan administrative fees, and advisory fees all reduce realized returns and are not separately modeled.
• Vesting schedules on employer contributions. Many employers require a period of service before matched funds fully vest; unvested match forfeited upon an early job change is not modeled here.
• Sequence-of-returns risk. A single flat annual return is applied every year; real markets deliver volatile, sequential returns, and the order in which good and bad years occur can affect a real portfolio's terminal value even at the same average return.

• Contributing less than the full match threshold. Failing to contribute at least up to your plan's match cap (6% in this example) means leaving free employer money on the table, effectively taking a pay cut relative to a coworker who captures it.
• Assuming the elective deferral limit includes employer contributions. The $23,500 cap applies to your own payroll deferrals; employer matching is a separate, additional pool of money subject to its own overall plan limit.
• Using an unrealistically high expected return. Historical long-run equity returns have generally landed in the 7-10% nominal range with meaningful year-to-year variance; entering an overly optimistic rate produces a projection that overstates likely retirement readiness.
• Ignoring vesting when changing jobs frequently. Job changes before employer contributions fully vest can forfeit thousands of dollars of matched funds that a static projection like this one assumes you keep.
• Forgetting that this models pre-tax growth. Traditional 401(k) withdrawals are taxed as ordinary income in retirement; the balance shown here is a pre-tax projection, not spendable after-tax income.

• Internal Revenue Service, Retirement Topics - 401(k) and Profit-Sharing Plan Contribution Limits, https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-401k-and-profit-sharing-plan-contribution-limits
• Internal Revenue Service, IRC Section 402(g) Elective Deferral Limits.
• U.S. Department of Labor, Employee Benefits Security Administration, 401(k) Plan overview, https://www.dol.gov/general/topic/retirement/typesofplans
• IRS Notice on SECURE 2.0 Act catch-up contribution provisions.