Roth or traditional early in a career versus at peak earnings

By DecisionSheet · Updated September 26, 2026 · 2026 tax figures

The usual framing of the Roth or traditional choice is a comparison of two tax rates: the rate saved today by deferring, and the rate paid on the money later. The first of those depends on the bracket a saver is in when contributing, which can differ between a first job and peak earnings. DecisionSheet's Roth vs. Traditional calculator turns that into one number, the break-even retirement tax rate: the effective rate in retirement at which the two paths end level. This page runs the same contribution at two career stages and shows how far that number moves, and what moves it.

At 12% from age 25 the break-even is 9.5%. At 32% from age 45 it is 28.2%. With the same 18% retirement rate assumed for both, the first saver's Roth ends $192,912 ahead, and the second saver's traditional path ends $44,384 ahead.

The two savers

Both contribute $10,000 a year, within the 2026 401(k) elective deferral limit of $24,500 (IR-2025-111), until age 65. Everything else is the calculator's default: a 7.5% annual return, which is an assumption and not a forecast, a 18% effective tax rate in retirement (the average rate across all withdrawals, not the top bracket), and the default taxes on the traditional path's invested tax savings. The two savers differ in exactly two inputs:

• Early career: age 25, marginal rate 12%. For 2026, a single filer pays 12% federal tax on taxable income from $12,400 to $50,400.
• Peak earnings: age 45, marginal rate 32%, the single-filer rate on taxable income from $201,775 to $256,225 (IRS, 2026 inflation adjustments).

The marginal rate is the rate on the last dollar earned. The calculator's field is meant to hold federal plus state; these scenarios use the federal rate alone, as for a state with no income tax.

How the model treats a career stage

The model holds today's rate fixed for every year of contributions. The early-career scenario is 40 years of $10,000 contributions, every one of them deducted at 12%; the peak-earnings scenario is 20 years at 32%. It has no way to raise the rate partway through, and contributions always run to the retirement age, so it cannot isolate a single year's contribution either. Each scenario is a saver who stays at one stage until retiring, which is a simplification of any real career.

On the traditional path the model invests the tax the deduction saves each year, $1,200 at 12% and $3,200 at 32%, in a taxable account. The Roth path has no such account.

The two stages side by side

Open each case: early career · peak earnings.

The 18% retirement assumption sits above the early saver's break-even and below the peak earner's, which is why the winner flips. The dollar amounts are not comparable across the two columns: the early saver contributes for 40 years and the peak earner for 20.

What moves the break-even

The two savers differ in two inputs at once, so the table alone cannot say which one matters. The calculator can: change one input at a time.

Raising today's rate from 12% to 32% lifts the break-even by 15.9 points at age 25 and 17.6 points at age 45. Starting at 45 instead of 25 lifts it by 1.1 points at 12% and 2.8 points at 32%. In this model the career stage matters to the Roth decision almost entirely through today's tax rate.

In the two cross cases the winner follows the rate, not the age: at age 25 and 32% the traditional path ends $167,339 ahead; at age 45 and 12% the Roth ends $32,074 ahead.

Why the break-even sits below today's rate

In every one of the four cases the break-even is below the rate paid today: by 2.5 points for the early saver, 1.4 points at 12% from age 45, 6.6 points at 32% from age 25, and 3.8 points for the peak earner.

That gap comes from the taxable account holding the invested savings. The model trims its return by a 0.4% annual tax drag (tax paid each year on dividends) and taxes its growth at 15% at the end. Set both of those to zero and the break-even equals today's rate at either stage: 12% for the early saver (open) and 32% for the peak earner (open). The table above shows the gap growing with both the horizon and today's rate. That is consistent with what the two charges act on: a longer horizon gives them more years, and a higher rate puts more money in the account ($576,401 at 32% from age 25, against $216,150 at 12%).

For the break-even itself, and the calculator's treatment of a near-tie, see Roth or traditional 401(k)? It comes down to one number.

Assumptions and limits

• One rate per career. Today's rate applies to every contribution until retirement. A career that moves through brackets cannot be represented in one run.
• Retirement rate. The 18% effective retirement rate is the same assumption for both savers. What rate either one would actually face depends on retirement income the model does not see.
• Federal rate only. The scenarios enter the federal bracket rate, with no state tax.
• Return. A constant 7.5% a year on all three accounts before the drag. It is an assumption, not a forecast.
• Invested savings. Every dollar of traditional tax savings is invested every year. The taxable account's cost basis grows only by the savings put in, so income the drag has already taxed is taxed again as a gain; this leans the comparison toward the Roth.
• Lump-sum valuation. Each account is valued at once at age 65. There is no withdrawal schedule, no required minimum distributions, and no employer match.
• Roth withdrawals are treated as tax-free, which under IRS rules holds for a qualified distribution: the account held at least five years and the withdrawal made after age 59½, on disability or at death (IRS Roth comparison chart).

Method and sources

The model is calculateRothVsTraditional in the Roth vs. Traditional calculator. It compounds the Roth, the traditional account and the taxable account holding the tax savings year by year, values all three after tax at the retirement age, and finds the break-even retirement rate by bisection against that same simulation, reported to one decimal. Every figure above comes from running the model on the inputs in the scenario links.

• IRS, tax inflation adjustments for tax year 2026 — single filers pay 12% on taxable income over $12,400 and 32% over $201,775; the next brackets start at $50,400 and $256,225.
• IR-2025-111 — the 2026 401(k) elective deferral limit of $24,500.
• IRS Roth comparison chart — Roth contributions are made with after-tax dollars and traditional contributions with before-tax dollars; the conditions for a qualified Roth distribution.

Open this scenario in the calculator

All figures on this page come from the Roth vs. Traditional calculator. Change any input there and the numbers update.