Roth 401(k) vs. Traditional 401(k): How the Tax Tradeoff Works

The Core Choice Is When You Pay Income Tax

Traditional 401(k) contributions generally reduce current taxable income, while withdrawals are generally taxable later. Designated Roth 401(k) contributions are made after tax, and qualified distributions can be tax-free. Neither is universally better; the choice depends largely on your tax situation now versus retirement.

Start With Today’s Marginal Tax Rate

A traditional contribution may be attractive when the current deduction saves tax at a rate you expect to be higher than your retirement rate. Roth contributions may appeal when you expect your future rate to be higher or value having a pool of qualified tax-free retirement money. Because future tax law and income are uncertain, the decision is an informed estimate.

The Contribution Limit Is Shared

For 2026, the IRS basic employee elective-deferral limit is $24,500 for most 401(k) participants. Traditional and Roth employee contributions share that limit; choosing both does not double it. Plans may allow catch-up contributions, and special 2026 rules can apply by age and income, so check current IRS guidance and your plan documents.

Employer Matching Has Its Own Treatment

An employer match can be valuable regardless of whether your employee contribution is Roth or traditional. How matching contributions are deposited and taxed depends on plan design and current rules. Review the summary plan description instead of assuming the employer money receives the same tax treatment as your election.

Splitting Contributions Can Reduce Guesswork

If your plan permits both options, you may divide contributions between them. This creates tax diversification: some retirement money may be taxable and some may be available tax-free if distribution requirements are met. A split can be a reasonable response when your current and future tax rates are difficult to predict.

Decide in the Right Order

First capture any employer match you can reasonably afford, then consider cash flow, current tax bracket, expected retirement income and other savings. Revisit the election after major income or family changes. A tax professional or fiduciary adviser can help with high-income, early-retirement or multi-state scenarios.