Roth IRA vs. 401(k): Which One Should Get Your Next Dollar?

The trade-off underneath both accounts

Every dollar you put toward retirement through either of these accounts eventually gets taxed once — the question is only when. A traditional 401(k), the default version most employers offer, lets you contribute pre-tax dollars: the money comes out of your paycheck before income tax touches it, your taxable income for the year goes down, and the account grows tax-deferred. The bill comes due later, when you withdraw in retirement and pay ordinary income tax on whatever you take out. A Roth IRA runs the trade in the other direction: you contribute money you’ve already paid income tax on, but if you follow the account’s rules — generally, the account has to be open a certain number of years and you have to be past a certain age — qualified withdrawals in retirement are tax-free, growth included.

Neither structure is universally better. A traditional 401(k) tends to favor someone who expects to be in a lower tax bracket in retirement than they are today — deferring the tax bill to a period when the tax rate on it might be lower. A Roth IRA tends to favor someone who expects the opposite, or who simply wants the certainty of paying tax at today’s known rate rather than betting on what rates and their own income will look like decades from now. Since nobody can know their exact future tax bracket with confidence, plenty of savers reasonably choose to split contributions between both kinds of accounts rather than picking one side of the bet entirely.

Why the employer match usually comes first

Here’s the piece that overrides the tax-preference debate for most people, at least up to a point: if your employer offers a matching contribution on your 401(k) — a common structure is matching some percentage of your own contribution up to a certain percentage of your salary — that match is essentially free money tied to a specific account. Skipping it to fund a Roth IRA instead means leaving compensation on the table that your employer would otherwise have paid you. Most financial guidance treats “contribute enough to get the full match” as the first move regardless of your tax preferences, simply because no other account on this list offers an immediate, guaranteed return anywhere close to a 50% or 100% match on your own contribution.

Once you’ve captured the full match, the tax-preference question becomes the more relevant one for where your next dollar goes — a Roth IRA (if you’re eligible), the rest of your 401(k) room, or some mix of both.

Contribution limits for 2026

Contribution limits on both account types are set by the IRS and adjusted annually for inflation, which means the specific dollar figures change most years and any number you read is only accurate for the year it’s quoted. For 2026, per the IRS’s published figures: the limit on employee 401(k) deferrals is $24,500, with an additional catch-up contribution for savers age 50 and up of $8,000 on top of that. The limit across all your IRAs combined — Roth and traditional together, since the limit is shared — is $7,500. Those are this year’s numbers specifically; check IRS.gov before relying on them for a future contribution year, since inflation adjustments move the figures most years.

Income limits: the Roth IRA’s catch

A 401(k) doesn’t care what you earn — anyone whose employer offers one can contribute, match or no match. A Roth IRA does care: the IRS phases out your ability to contribute directly to a Roth IRA once your income crosses certain thresholds, and above a higher threshold you can’t contribute to one directly at all. Those income thresholds are also adjusted annually and are a separate figure from the contribution limit itself, so a high earner who wants Roth-style tax treatment sometimes ends up using a “backdoor” conversion process instead of contributing directly — a more involved maneuver that’s worth discussing with a tax professional rather than assuming it’s automatic.

Withdrawal rules and flexibility

The two accounts also differ in how forgiving they are if you need the money before retirement. A Roth IRA lets you withdraw your original contributions — not the earnings — at any time, for any reason, without tax or penalty, since you already paid tax on that money going in. That flexibility doesn’t extend to withdrawing earnings early, which generally does trigger tax and a penalty outside of a narrow set of exceptions. A traditional 401(k) is considerably less forgiving about early access: withdrawals before the standard retirement age typically trigger both ordinary income tax and an early-withdrawal penalty, with only limited exceptions such as certain hardships or specific loan provisions some plans offer.

Which to prioritize

A reasonable, commonly used order looks like this: first, contribute enough to your 401(k) to capture the full employer match. Second, if you’re eligible for a Roth IRA and value tax-free growth or the withdrawal flexibility, fund that up to its annual limit. Third, if you still have money to save and haven’t hit your 401(k)‘s limit, route additional contributions back to the 401(k). That order isn’t a universal rule — someone with no employer match, or one who strongly expects a lower tax bracket in retirement, might reasonably weight things differently — but it reflects the two considerations that matter most for most savers: never leave a guaranteed match unclaimed, and decide your tax-now-versus-tax-later preference deliberately rather than by default.

The bottom line

A traditional 401(k) and a Roth IRA aren’t competing versions of the same product — they’re the same tax trade-off run in opposite directions, plus a 401(k)‘s employer match, which usually settles the “which first” question before the tax debate even starts. Confirm this year’s actual contribution and income limits before you plan around them, since the specific numbers move with inflation every year and the 2026 figures quoted above are flagged here for that exact reason.