401(k) Calculator

How the calculator projects your 401(k)

A 401(k) grows from three sources: the part of your pay you defer, the money your employer adds as a match, and the investment return on everything already in the account. The calculator follows those year by year from now until the year before your retirement age:

1. Your pay starts at the salary you enter and rises once a year by your raise.
2. Your contribution is your percentage of that pay, cut back to the IRS limit for your age if it would go over.
3. The match is worked out from the formula you enter, on the percent of pay you actually deferred.
4. Growth: contributions arrive monthly and the balance compounds at your expected return.

Unlike the retirement calculator, which plans the whole journey including withdrawals, this page focuses on the workplace plan itself: how the match works, what the limits allow and how much money you give up by contributing less than your employer will match.

2026 401(k) contribution limits

For 2026 the IRS set these limits (News Release IR-2025-111 and Notice 2025-67):

• $24,500 of elective deferrals, traditional and Roth combined, across all the 401(k), 403(b) and governmental 457 plans you take part in.
• $8,000 of extra catch-up contributions if you are 50 or older by the end of the year, for a total of $32,500.
• $11,250 instead of $8,000 if you turn 60, 61, 62 or 63 during the year, a higher catch-up created by the SECURE 2.0 Act. Your total can then reach $35,750.
• $72,000 for everything that goes into your account in a year from you and your employer together, not counting catch-up contributions (and never more than your pay).
• $360,000 of pay is the most a plan can use to work out contributions such as the match.

From 2026, if your wages from the employer were over $150,000 in the previous year, catch-up contributions in a plan that offers Roth must be made as Roth. The IRS adjusts the dollar limits for inflation most years; the calculator keeps them at the 2026 amounts, so for long projections it may cap contributions a little earlier than your plan would.

The formulas

Each year, your contribution and the match are:

c

the percent of pay you defer (after the limit)

m₁, u₁

first tier: the match rate and the percent of pay it applies to (100% up to 3%)

m₂, u₂

second tier: the match rate on the next slice of pay (50% of the next 2%)

You receive the full match once c reaches u₁ + u₂. The balance then grows each year by

where r is the annual return and i = (1 + r)^(1/12) − 1 is the monthly rate that compounds to it, because the year’s contributions arrive in twelve monthly amounts rather than all on day one.

Worked example

You are 35, earn $75,000 and get 3% raises. You defer 4% of pay, and your employer matches 100% of the first 3% plus 50% of the next 2%. You already have $25,000 saved and expect a 6% return until you retire at 67.

1. Your contribution this year: $75,000 × 4% = $3,000
2. The match: 100% × 3% + 50% × 1% = 3.5% of pay, or $2,625
3. After one year: $25,000 + $3,000 + $2,625 + $1,653.06 of growth = $32,278.06
4. After 32 years: $908,303.68, made of the $25,000 you started with, $157,508.26 of your own contributions, $137,819.72 of match and $587,975.70 of investment growth.

Deferring 5% instead of 4% would raise this year’s match from $2,625 to $3,000. At 4%, you give up $375 of match this year and $19,688.54 over the 32 years, before any growth on it.

Traditional or Roth 401(k)?

Many plans let you choose how your own contributions are taxed. The limits above apply to both combined, and this calculator shows the balance before any tax, whichever you pick.

• Traditional (pre-tax): contributions reduce your taxable income now. Withdrawals in retirement, contributions and growth alike, are taxed as ordinary income.
• Roth: contributions come out of pay that has already been taxed, so they don’t lower this year’s tax. A qualified withdrawal, made at least five years after your first Roth contribution and after age 59½ (or on disability or death), is tax-free, growth included.

Traditional tends to suit people who expect a lower tax rate in retirement than today; Roth suits those who expect the same or higher. Either way both kinds are still subject to Social Security and Medicare tax when you earn them. See the effect on your pay with the paycheck calculator.

What the projection leaves out

• Vesting. Matching money may only become yours after a number of years of service. If you leave early you can lose some of it.
• Plan details. Some plans match each paycheck rather than the whole year (a “true-up” fixes this), cap the match in dollars, or add profit-sharing contributions.
• Inflation and taxes. The balance is in future dollars before tax. The inflation calculator shows what a future amount is worth today.
• Market swings. Returns vary from year to year; a constant average gives a smooth path that real accounts won’t follow.