401(k) Calculator

Less than growth on what you already have, but still a meaningful amount. With the calculator's defaults, a 58-year-old with $850,000 who contributes 18% of a $175,000 salary reaches $1,620,605 at 65. Of the $770,000 increase, $231,206 is her own contributions, $39,030 is the employer match and $500,369 is investment growth. Contributing only enough for the match would leave her at $1,426,231, so the extra saving is worth about $194,000.

The lesson for late savers is not that contributions stop mattering. It is that the balance you already hold now drives the result, so the return you earn on it in the years around retirement, and the date you stop work, move the outcome more than a few extra points of salary. Working two more years, to 67, takes the same saver to $1,905,175.

The employee limit rises at 50 and again, for four years only, from 60 to 63. The age that counts is the age you reach by the end of the calendar year (IRS, 2026).

The calculator applies the right limit at each age and caps any year in which your percentage of pay would exceed it; those years carry an asterisk in the table. Employer contributions sit outside these figures under a combined limit of $72,000 a year, plus catch-ups. The IRS usually raises the limits for inflation each autumn, so the projection, which holds 2026 limits constant, is slightly conservative for anyone contributing at the maximum.

Because SECURE 2.0 requires it for higher earners from 2026. If your wages from the employer sponsoring the plan were more than $150,000 in the prior year, any catch-up contribution you make must go into the plan's Roth option (IRS). Only the catch-up is affected; the base $24,500 can still go in pre-tax.

For the default saver, that means $24,500 of this year's $31,500 lowers taxable income and $7,000 goes in as Roth. At a 24% marginal rate, the tax saving is $5,880 rather than $7,560. The calculator uses your salary as a stand-in for last year's wages; if your pay has changed a lot, check the figure on last year's W-2 (box 3, Social Security wages, is the relevant measure).

Many savers near retirement will not mind. A Roth balance is not counted when required minimum distributions are calculated, it is not taxable when withdrawn after 59½ once the account has been open five years, and it leaves heirs a tax-free inheritance. The Roth vs. traditional guide sets out the comparison.

Pre-tax usually wins while you are in a high bracket and expect a lower one later. The case weakens when a large traditional balance is already set to produce big required distributions. Three things push later tax rates up: RMDs that start at 73, or 75 if born in 1960 or later, and grow as a share of the account each year; up to 85% of Social Security becoming taxable once other income is high; and Medicare's income-related premium surcharges, based on income from two years earlier. A surviving spouse also moves to the single brackets on much the same income.

Households with $1 million or more in pre-tax accounts often split contributions, or keep contributing pre-tax and then convert to Roth in the low-income years between retiring and claiming Social Security. The guide to Roth conversions before RMDs and the RMD calculator show how large those distributions could be.

You choose whether to leave it, roll it to an IRA, or split it. The choices that matter most:

• Access before 59½. If you leave the employer in or after the year you turn 55, withdrawals from that employer's plan avoid the 10% additional tax (IRS). The exception does not follow the money into an IRA.
• Rolling over. A direct rollover to an IRA avoids withholding and keeps the money tax-deferred; an indirect rollover must be completed within 60 days (IRS). Compare the plan's fund costs with what you would pay in an IRA before moving it.
• Company stock. Shares of your employer held in the plan may qualify for net unrealized appreciation treatment if distributed in kind, which taxes the growth at capital gains rates. Rolling the shares to an IRA gives that up. Get advice before you move them.
• Required distributions. While you still work for the employer, you can usually delay RMDs from its plan until you retire, unless you own more than 5% of the company (IRS).
• Beneficiaries. The beneficiary form on the plan decides who inherits it, whatever your will says. Federal law gives a spouse rights to most 401(k) balances unless the spouse has signed a waiver.

How you then draw on the money, and in what order across taxable, pre-tax and Roth accounts, is covered in the retirement withdrawal order guide.

• Market swings. A steady return is assumed. A fall in the last two or three years before retirement can erase several years of contributions, which is why many savers shift part of the account to bonds and cash as the date nears.
• Fees. Enter a return net of fund and plan fees. A 1% advisory fee on top of fund costs is a large share of a 6% return.
• Future limit increases. Limits are held at 2026 levels.
• Taxes on withdrawals. The balance is pre-tax for traditional money. The 4% income figure is before tax.
• Other savings. IRAs, a spouse's plan and taxable accounts are not included; the retirement calculator brings them together with Social Security.