What a 401(k) actually is
A 401(k) is a retirement account offered through an employer - contributions come straight out of your paycheck before you ever see the money, which is a big part of why it works so well as a savings habit. Your employer picks the investment options; you pick how much to contribute and where, within that menu.
There's an annual IRS limit on how much you can contribute, and it typically adjusts most years - it's worth checking the current cap directly rather than assuming last year's number still applies.
Traditional vs. Roth: the tax question
Both 401(k)s and IRAs usually come in two flavors, and the difference is entirely about when you pay tax.
A traditional account lowers your taxable income this year - you get the tax break now, and pay ordinary income tax when you withdraw in retirement. A Roth account is the mirror image: you contribute after-tax dollars now, but withdrawals in retirement (including all the growth) are tax-free.
The rule of thumb: if you expect to be in a lower tax bracket in retirement than you are now, traditional tends to win. If you expect to be in the same or a higher bracket later - common earlier in a career, or if tax rates rise - Roth tends to win. Splitting contributions between both is a reasonable way to hedge that uncertainty.
The employer match is the closest thing to free money
If your employer matches a percentage of what you contribute, that match is an instant, guaranteed return that nothing else in investing can match - not even a good year in the market. Before optimizing anything else about your savings - which account type, which funds, how aggressive to be - it's almost always worth contributing at least enough to capture the full match.
Why starting early matters so much
Retirement contributions grow through compounding - the returns you earn start earning their own returns. That means time in the market matters more than almost any other single factor: a smaller monthly amount started in your 20s can end up outpacing a larger amount started in your 40s, simply because it had decades longer to compound.
A common rule of thumb is aiming for somewhere around 15% of income toward retirement over a working life, though the right number for you depends heavily on when you started and when you'd like to stop working.
IRAs: what they add beyond a 401(k)
An IRA (individual retirement account) works outside of an employer - you open one yourself with a broker, and it comes in traditional and Roth versions with the same tax logic as above. IRAs usually have a lower annual contribution limit than a 401(k), and Roth IRAs specifically phase out at higher incomes, so they're often used to supplement a 401(k) rather than replace it, or as the main vehicle if you don't have an employer plan at all.
Practical ways to increase how much you save
- Capture the full employer match first - it's the highest-return move available to most savers.
- Automate contributions so they happen before you have a chance to spend that money elsewhere.
- Increase your contribution percentage with each raise, before your budget adjusts to the new income.
- Pay down high-interest debt to free up more room for savings - guaranteed interest saved usually beats an uncertain investment return.
- Take advantage of catch-up contributions once you're eligible - both 401(k)s and IRAs allow higher limits starting at age 50.
Putting a number to it
Once you have a target monthly contribution in mind, it's worth checking how that number actually fits alongside your income, existing debt, and the rest of your budget - not just whether you can technically afford the contribution, but what it leaves you for everything else.