Can I contribute to both Roth and Traditional?

Yes — many savers split contributions to diversify future tax exposure, since nobody knows future tax rates for certain.

Roth vs Traditional 401(k) Calculator

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Roth vs Traditional

After-tax value • Break-even

Annual contribution (pre-tax)

Years until retirement

yrs

Expected annual return

Tax rate now

Tax rate in retirement

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Enter your plan to compare Roth vs Traditional

How the Roth vs Traditional Calculator Works

Enter your contribution, years, and return.
Set your tax rate now and in retirement.
See the after-tax value of each — the only fair comparison — and which wins.

Roth vs Traditional: The Honest Comparison

The whole decision comes down to one thing: your tax rate now vs in retirement. A Traditional 401(k)/IRA deducts contributions today and taxes withdrawals later. A Roth is funded with after-tax dollars and grows tax-free. Comparing the same pre-tax contribution, the after-tax result is simply: Traditional = future value × (1 − retirement rate); Roth = future value × (1 − today's rate).

So Roth wins if your tax rate will be higher in retirement (or you're young/low-bracket now); Traditional wins if your rate will be lower later. When the rates are equal, they tie. Many people split contributions to hedge. Estimate only; not tax advice.

Formula & Logic

The Roth-versus-traditional decision reduces to a single comparison: your marginal tax rate now versus your marginal rate when you withdraw. Traditional contributions are deducted today and taxed later; Roth contributions are taxed today and withdrawn free. If the two rates are identical the mathematics is exactly a wash — the commutative property of multiplication means taxing at the start or the end gives the same result. Everything else is a tiebreaker: Roth has no required minimum distributions, is better for heirs, and hedges against future rate rises, while traditional wins if you will genuinely retire into a lower bracket.

Traditional after-tax = C × (1 + r)^n × (1 − tax_retirement)Roth after-tax = C × (1 − tax_now) × (1 + r)^nEqual when tax_now = tax_retirement

where:

C: pre-tax amount available to contribute
tax_now: your marginal rate today
tax_retirement: expected marginal rate on withdrawal
r, n: return and years

Assumptions: Assumes the same investment and return in both. A hidden advantage of Roth: the $7,000 limit is an after-tax limit, so a maxed Roth shelters more real money than a maxed traditional account.

Step-by-Step Example: $7,000 at 22% Now Versus 24% Later

Compare both routes over 25 years at 7%, for someone expecting a slightly higher rate in retirement.

Contribution$7,000
Rate now22%
Rate in retirement24%
Horizon25 years at 7%

Growth factor: 1.07^25 = 5.4274.
Traditional — the full $7,000 goes in and grows: $7,000 × 5.4274 = $37,992.
Tax it on withdrawal at 24%: $37,992 × 0.76 = $28,874.
Roth — tax first at 22%: $7,000 × 0.78 = $5,460 actually invested.
Grow it, then withdraw tax-free: $5,460 × 5.4274 = $29,634.
Roth wins by $760, purely because the future rate is 2 points higher.

ResultRoth $29,634 versus traditional $28,874 — a $760 edge

Flip the rates — 24% now, 22% later — and traditional wins by a similar margin. The decision is genuinely close in most cases, which is why many people split contributions between both and treat it as tax diversification rather than a bet on future legislation.

Roth vs Traditional FAQ

Is Roth or Traditional better? ▾

Roth is better if your tax rate in retirement will be the same or higher than today; Traditional is better if it will be lower. Young savers and those in low brackets usually favor Roth.

Why compare after-tax values? ▾

A Traditional balance still owes taxes at withdrawal, while a Roth doesn't — so comparing pre-tax balances is misleading. The after-tax value is the true apples-to-apples figure.

Can I do both? ▾

Yes — many savers split contributions between Roth and Traditional to diversify their future tax exposure, since nobody knows future tax rates for certain.