401(k) vs Roth IRA: Which Retirement Account Should You Use?
Two of the most powerful retirement accounts in the US are the 401(k) and the Roth IRA. They are not either-or — many people use both — but understanding how each handles taxes helps you decide where your next dollar should go.
The core tax difference
A traditional 401(k) is funded with pre-tax money: you get a tax break now, your investments grow tax-deferred, and you pay income tax when you withdraw in retirement. A Roth IRA is the reverse: you contribute money you have already paid tax on, and qualified withdrawals in retirement are completely tax-free. In short, a 401(k) taxes you later, a Roth taxes you now.
Other key differences
- Employer match: many 401(k) plans match part of your contributions — effectively free money a Roth IRA cannot offer.
- Contribution limits: 401(k)s allow much higher annual contributions than IRAs.
- Investment choice: IRAs usually offer far more investment options than a typical 401(k) menu.
- Income limits: Roth IRA eligibility phases out at higher incomes; 401(k)s do not have that cap.
A simple order of priority
- Contribute to your 401(k) at least enough to capture the full employer match — never leave that free money behind.
- Then consider funding a Roth IRA, especially if you expect higher taxes in retirement.
- If you still have room, return to the 401(k) up to its higher limit.
Traditional or Roth — which is better?
It largely depends on whether your tax rate is higher now or expected to be higher in retirement. Roth wins if taxes will be higher later; traditional wins if they will be lower. Many people split the difference by using both.
What if my employer offers a Roth 401(k)?
A Roth 401(k) combines the high contribution limit and match of a 401(k) with Roth tax treatment — a strong option. The match itself typically still goes into the pre-tax side.
The bottom line
Capture your full 401(k) match first, then weigh a Roth IRA for tax-free growth, then top up the 401(k) further. The right mix depends on your taxes now versus later — and using both is often the smartest play. Project the long-term picture with our free retirement calculator.