What the accounts actually are, why the employer match comes first, and why starting early beats starting big. General information, not personalized financial or tax advice.
This trips up more first-time savers than anything else on this page. "I have a 401(k)" describes the account, not what is inside it. The account is a wrapper with tax rules; the money inside still has to be invested in something, usually a set of funds your plan offers. It is entirely possible to contribute faithfully for years into a plan that quietly parked everything in a cash-equivalent option, and to end up with roughly what you put in.
Most plans now default new contributions into a target-date fund, named for roughly the year you would retire, which holds a mix of stocks and bonds and shifts gradually toward bonds as that year approaches. That default is a reasonable starting point for someone who does not want to make the decision. The thing worth doing once, early, is logging in and confirming what your money is actually invested in, rather than assuming the account is doing the work by itself. How asset classes work covers what those underlying holdings actually are.
If your employer matches contributions, that match is part of your compensation, and declining to contribute enough to earn it is declining part of your pay. A common structure is 50% of what you put in, up to 6% of your salary. On a $60,000 salary, contributing $3,600 a year earns another $1,800 a year that you did not have to fund. That is a 50% return on the contribution, immediately, before the market does anything at all. No investment reliably offers that.
It compounds like everything else, too. That $1,800 a year of match alone, invested for 30 years at a 7% average return, comes to roughly $182,996 — money that originated entirely from the employer, purely because the contribution was large enough to trigger it. This is why "contribute at least up to the match" is the one piece of retirement advice that is close to universal.
One caveat worth knowing early: matched money may be subject to a vesting schedule, meaning you earn ownership of it over a period of service. Your own contributions are always yours immediately. The employer's portion may not be, and leaving before you vest can forfeit some of it. It is worth knowing your plan's schedule before timing a job change.
A traditional contribution comes out of your pay before income tax, lowering this year's taxable income, and is then taxed as ordinary income when you withdraw it in retirement. A Roth contribution is made from already-taxed pay, so it does nothing for this year's tax bill, and qualified withdrawals in retirement come out entirely tax-free, growth included.
Strip away the jargon and the question is only this: do you expect your tax rate to be higher now or higher when you withdraw? If you are early in your career and expect to earn more later, paying the tax now at a lower rate, via Roth, is the argument. If you are in a high-earning year and expect a lower rate in retirement, taking the deduction now, via traditional, is the argument. Nobody knows future tax rates, which is why plenty of people end up holding some of each rather than trying to be right.
Roth IRAs also have income limits that 401(k)s do not. For 2026 the ability to contribute to a Roth IRA phases out between $153,000 and $168,000 of income for single filers, and between $242,000 and $252,000 for married couples filing jointly. A Roth 401(k), where a plan offers one, has no such income limit.
These are IRS limits, adjusted most years for inflation, and they reset every January. The workplace-plan limit and the IRA limit are separate, so contributing the maximum to a 401(k) does not use up your IRA allowance.
Two of those deserve a note. The $72,000 figure is the combined ceiling on everything landing in your workplace account in a year, your contributions plus the employer's, which is why it is far higher than the $24,500 you can defer yourself. And the ages 60 to 63 catch-up is a genuinely unusual provision: it is larger than the standard age 50 catch-up and applies only in that narrow window. For most people starting out, none of these are binding constraints. The $24,500 limit works out to about $2,041.67 a month, which is well past what most early-career savers are contributing.
If your income is modest, there is also a credit worth knowing about. The Saver's Credit gives a tax credit for retirement contributions to filers under certain income limits, which for 2026 are $80,500 for married filing jointly, $60,375 for head of household, and $40,250 for single filers. It is one of the few provisions that specifically rewards saving on a lower income, and it is routinely missed.
Take someone contributing $300 a month at a 7% average annual return. Starting at 25 and running 40 years produces about $787,444, of which $144,000 is money they put in and roughly $643,444 is growth. Starting the identical contribution at 35 instead, for 30 years, produces about $365,991.
The ten-year delay costs about $421,453. The contributions skipped in that decade total $36,000. So the missing money is not really the $36,000 — it is the four decades of compounding those particular early dollars would have had, which is the part that cannot be bought back later by contributing harder. This is the entire reason "start now, even small" is repeated so relentlessly, and it is the one piece of retirement advice that becomes strictly less useful the longer you wait to hear it.
A 7% average return is an assumption, not a promise: real markets deliver that as an average across decades containing some sharply negative years. How interest works explains the compounding mechanism itself, and the retirement calculator will run these numbers on your own contribution and timeline.
Small amounts started early beat larger amounts started late, because the variable doing the work is time rather than size. The example above is the same $300 a month in both cases; the only difference is when it began, and that difference is about $421,453. Waiting to contribute until you can contribute "properly" spends the one input you cannot get back.
It is genuinely hard to reach early, and that is deliberate: withdrawals before age 59½ generally trigger an additional tax on top of ordinary income tax, with a limited set of exceptions. But "hard to access" is not "gone", and the illiquidity is doing a job. Retirement money that is easy to spend tends to get spent. It should not be your emergency fund, which is a separate thing you keep accessible.
The decisions that dominate outcomes are how early you start, how much you contribute, whether you capture the full match, and whether you leave it alone through downturns. Fund selection matters far less than any of those, which is why a default target-date fund is a perfectly respectable answer. Waiting until you feel qualified to choose is more expensive than choosing the default today.
Usually a reasonable default, but it is a rule of thumb rather than a law. Roth wins if your tax rate is lower now than at withdrawal, which is typical early in a career but not universal — a high earner in an expensive year may do better taking the deduction. And the choice is not permanent or exclusive: many people accumulate some of both over a career, which hedges a tax rate nobody can forecast.
Limits are set by the IRS and adjusted most years for inflation. These apply to the 2026 tax year; check the current figures before relying on them in a later year.
Contribute enough to capture the full employer match first, because nothing else available to you returns 50% instantly. Keep a cash emergency fund separately and accessibly, since the fastest way to undo retirement progress is having to raid it. Clear genuinely high-interest debt next: paying off a balance at 22% is a guaranteed return that beats an uncertain 7%, which is the same logic the debt payoff calculator runs on. Then increase the contribution rate as your income grows, ideally on the same day a raise lands, before the money is spoken for.
What this order deliberately does not include is picking the right fund, timing an entry point, or waiting until you understand markets. Those are either low-impact or actively counterproductive at the start. The high-impact moves are unglamorous and mostly administrative: enrol, capture the match, confirm the money is actually invested, and raise the percentage when you can.
Nothing is saved or sent anywhere; this just checks your answers in the page itself.
The 7% average return used in the examples is an assumption for illustration and not a projection; actual returns vary year to year and can be negative. This page is general information, not financial or tax advice, and your own plan's rules, match formula and vesting schedule are set by your employer. Contribution limits change most years, so confirm the current figures at IRS.gov before acting on them.