Traditional vs Roth 401(k)

Same account, two tax treatments. Traditional gives you a deduction now; Roth gives you tax-free withdrawals later. Whether either wins depends on whether you'll be in a higher or lower bracket in retirement.

Your assumptions

$
$23,000/yr 2025 limit, $30,500 if 50+.
%
%
Federal + state. The bracket the contribution comes from.
%
Effective rate when withdrawing (usually lower than current).

Traditional 401(k)

Pre-tax contribution

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Balance at retirement

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After-tax withdrawal value

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Tax saved now (each year)

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Roth 401(k)

After-tax contribution cost

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Balance at retirement

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After-tax withdrawal value

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Tax saved later (cumulative)

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The simple rule

If your tax rate now is higher than your tax rate in retirement, Traditional wins. If your tax rate now is lower than your tax rate in retirement, Roth wins. If they're equal, it's a tie.

This is the entire decision in one sentence. Everything else is detail or hedge.

Why people overcomplicate it

You'll see arguments about compounding, RMDs, tax-bracket creep, and so on. They're all real but secondary. The first-order math is just: which tax bracket do you want to pay in? Pay tax now at your current rate, or pay tax later at your retirement rate.

Why most people will be in a lower bracket in retirement

  • No FICA (Social Security + Medicare taxes) on retirement distributions.
  • No mortgage to deduct, but standard deduction is still big.
  • Withdrawal needs are usually less than working income (no commute, less dining out, mortgage paid off).
  • Social Security covers part of expenses, so your 401(k) withdrawal is smaller.

So for most middle-and-upper-middle earners, Traditional has a slight edge. But there are exceptions.

When Roth makes more sense

  • You're young + low-income now. You're in the 12% bracket now and expect to be in the 24% bracket in 30 years.
  • You expect future tax rates to rise. National debt + entitlement pressures suggest higher future taxes. Roth locks in today's rate.
  • You'll have large taxable income in retirement. Pensions + Social Security + rental income could push your retirement bracket high.
  • You want flexibility. Roth has no Required Minimum Distributions (RMDs) at 73, unlike Traditional. Useful if you don't need the money.
  • Estate planning. Roth assets pass to heirs tax-free; Traditional doesn't.

The split-the-difference move

Many people split contributions: half Traditional, half Roth. This hedges the tax-rate-prediction risk. You get some current deduction, some future tax-free, and you don't have to be right about which rate will be higher.