401(k) Calculator

Introduction

This 401(k) Calculator estimates how your workplace retirement account grows when you defer part of each paycheck, receive an employer match, and earn compound returns until retirement. Enter salary, your contribution percent, the match formula, expected return, and years left to work. The output separates employee deferrals, employer match, and investment growth so you can see which piece drives the total. Use it before open enrollment to test whether bumping deferral one percent is worth more than chasing a hotter fund menu.

Who this calculator is for

Employees with access to a traditional or Roth 401(k) who want to quantify the value of the company match. It is especially useful when HR describes match as fifty cents on the dollar up to six percent and you need that translated into future dollars. New hires deciding how much to defer on day one and mid-career workers comparing Roth versus pre-tax deferral at a high level also benefit, though detailed tax tradeoffs belong in the IRA comparison tools.

Self-employed workers without a 401(k) should use SEP-IRA or solo 401(k) planning resources instead. If you already retired and take Required Minimum Distributions, switch to the RMD Calculator. For whole-portfolio retirement adequacy, layer this result into the Retirement Calculator.

What it estimates

The model compounds your deferrals, adds employer match according to the formula you enter, and applies the annual return you assume on the combined balance each year until retirement. Typical output includes total account value, cumulative employee contributions, cumulative employer match, and earnings. Some versions show a year-by-year table so you can see when match and growth overtake raw deferrals.

It does not model vesting schedules that forfeit employer match if you leave early, loan balances, hardship withdrawals, or plan fees broken out by fund. If your plan caps match at a dollar amount regardless of salary, enter the cap if the form allows. Read 401(k) employer match guide for vesting and true-up rules your plan document may include.

Inputs explained

Match formulas vary by employer. Enter the formula exactly as your summary plan description states it, not as you wish it worked.

• Annual salary: Gross pay used for match calculations; exclude bonus if match applies only to base.
• Employee deferral rate: Percent of salary you contribute each pay period.
• Employer match rate: Share of your deferral the employer pays, such as 50% or 100%.
• Match cap: Maximum deferral percent eligible for match, often 4% or 6% of salary.
• Current 401(k) balance: Existing account value if the form supports a starting balance.
• Expected annual return: Long-run average before fees; adjust down for conservative planning.
• Years to retirement: Working years left for contributions to continue.

How to read the results

Total balance at retirement is the headline number for comparing deferral scenarios. The split between your money, match, and earnings tells a richer story. If earnings are the largest slice, time and return did the heavy lifting. If employee deferrals dominate, you are early in career or using a low return assumption. Leaving match on the table shows up immediately when deferral falls below the cap: match line stays flat while a one-point deferral increase fills it.

Compare two runs: current deferral versus deferral at the match cap. The difference is the cost of ignoring free money. Then compare deferral at the cap versus deferral above the cap; only the employee slice grows in the match portion above the cap. Pair results with the Take-Home Pay Calculator to see paycheck impact of each deferral step.

Worked example

Salary $78,000, deferral 6%, employer match 50% on the first 6%, 7% annual return, 20 years to retirement, starting balance $0. You defer $4,680 per year. Match is half of that deferral up to the cap, $2,340 per year. Combined annual addition is $7,020 before growth. Over 20 years at 7%, employee contributions total about $93,600, match about $46,800, and earnings compose the rest for an ending balance near $300,000.

Drop deferral to 3% and match falls to $1,170 per year. You lose $1,170 of free match annually plus compounding on that amount, which can cost six figures by retirement. Raise deferral to 10% and match stays capped at $2,340 because the formula maxes at 6% of salary. The extra 4% deferral still helps, but only on your side of the ledger. That distinction matters when budgeting.

Practical use cases

Open enrollment: test 4%, 6%, and 10% deferral side by side. Job offer comparison: two salaries with different match formulas may differ more in retirement wealth than in base pay. Catch-up contributions after age 50: add the catch-up dollar amount to deferral if the calculator accepts dollars as well as percents.

High earners hitting annual deferral limits: once you max the IRS employee limit, match may still apply on eligible compensation depending on plan design; confirm with payroll. Roth 401(k) deferrals count toward the same limit but grow tax-free; this calculator may treat tax status as labels only, so use the Roth IRA Calculator for detailed tax breakeven.

Limitations and related tools

Vesting cliffs, non-elective employer contributions, after-tax mega backdoor buckets, and plan loans are not modeled. Investment menu performance varies; a single return assumption smooths good and bad decades. IRS contribution limits change; verify current-year caps on irs.gov before maxing deferral.

Broader retirement picture: Retirement Calculator. IRA outside work: IRA Calculator. Paycheck effect: Take-Home Pay Calculator. Further reading: 401(k) employer match guide and retirement savings by age.

How It Works

1. Enter salary and deferral. Type gross salary and the percent you contribute from each paycheck.
2. Set the match formula. Enter employer match rate and the maximum deferral percent that receives match, such as 50% on 6%.
3. Choose return and horizon. Pick expected annual return and years until retirement. Add current balance if available.
4. Review the three-way split. Calculate and compare employee, match, and earnings. Rerun with deferral at the match cap.

Formula and methodology

The 401K Calculator uses this identity for the scenario you enter. A bank, payroll system, or tax program may round on a 360-day year or average daily balance, so a statement can differ by a small amount.