Roth IRA vs traditional IRA

The core difference: when you pay tax

A Roth IRA asks you to pay tax before the money enters the account. If the distribution is qualified, future earnings can be withdrawn free of federal income tax. A traditional IRA often works in the opposite direction: eligible contributions may reduce taxable income today, investments grow tax-deferred, and withdrawals are generally taxed later as ordinary income. Both accounts can shelter investment growth while the money remains inside the account, but they allocate the tax bill to different points in time.

The simple rule of thumb is that Roth tends to look better when your tax rate in retirement will be higher than your tax rate today, while traditional tends to look better when today's tax rate is higher than your future tax rate. That rule is incomplete, but useful. It ignores deduction limits, phase-outs, invested tax savings, state taxes, required minimum distributions, estate goals, and cash-flow constraints. A good comparison keeps those variables visible instead of pretending one account is always superior.

For 2026, the IRA contribution limit is $7,500 under age 50 and $8,600 at age 50 or older, including the $1,100 catch-up amount. That limit applies across traditional and Roth IRAs combined. A saver choosing between the two wrappers is usually deciding where the same contribution dollars should go, not doubling the annual IRA limit.

Roth IRA: pros, cons, and who it is for

The Roth IRA's biggest advantage is tax certainty on qualified withdrawals. A young saver in a low tax bracket can pay tax now, let investments compound for decades, and potentially withdraw the earnings tax-free later. Roth IRAs also have no lifetime required minimum distributions for the original owner, which can help retirees manage taxable income and preserve optionality. Contributions, because they were after-tax, are generally more flexible than earnings under IRS ordering rules.

The tradeoff is the lost current deduction. If a household is in a high federal and state tax bracket today, a deductible traditional IRA contribution could free up meaningful cash. Roth contributions can also be restricted by modified adjusted gross income. For 2026, direct Roth IRA contributions phase out for single filers from $153,000 to $168,000 and for married filing jointly from $242,000 to $252,000. High-income users may need to study backdoor Roth rules rather than assuming a direct contribution is available.

Roth is often attractive for early-career workers, workers temporarily in a low-income year, people expecting higher future tax rates, and retirees who value tax diversification. It can also fit estate-planning goals because heirs may receive a tax-free-income asset, though inherited IRA distribution rules still matter. The account is less compelling when current tax rates are unusually high and future taxable income is expected to fall sharply.

Traditional IRA: pros, cons, and who it is for

A traditional IRA's main advantage is potential tax relief today. If a contribution is deductible, the taxpayer lowers current taxable income. A $7,500 deductible contribution at a 24% marginal federal tax rate can reduce the federal tax bill by about $1,800 before considering state tax effects. That immediate cash-flow benefit can be valuable for workers in peak earning years, especially if they expect a lower marginal rate in retirement.

The drawbacks appear later. Traditional IRA withdrawals are generally taxable as ordinary income, and pre-tax IRA balances can increase required minimum distributions after the applicable starting age. Traditional IRA deductions can also be limited when a taxpayer or spouse is covered by a workplace retirement plan. A non-deductible traditional IRA contribution has different economics than a deductible contribution, and it creates basis that must be tracked on tax forms.

Traditional can fit savers who need the current deduction, expect materially lower retirement tax rates, or are not eligible for direct Roth IRA contributions and do not want to handle conversion complexity. It can also be useful when a taxpayer wants to reduce current adjusted gross income for credits, deductions, or other planning reasons. But the account is not simply “better because it saves tax today”; the future withdrawal tax is the other half of the deal.

The break-even tax rate

The cleanest Roth-versus-traditional math starts with a simplified case: same contribution, same investment return, same time horizon, and no deduction invested separately. If the current tax rate and future withdrawal tax rate are identical, Roth and traditional can produce the same after-tax result. Roth pays tax before contribution; traditional pays tax after growth. Multiplication order does not matter when the tax rate is the same and all other assumptions are equal.

Example: suppose a saver can put $7,500 into a Roth IRA after tax, or put $7,500 into a deductible traditional IRA. If both grow to $57,000 and the future withdrawal tax rate is 22%, the traditional after-tax value is $44,460. A true equal-cost comparison asks what happened to the tax deduction. If the Roth saver paid tax out of pocket while the traditional saver kept the deduction savings, those extra dollars must be accounted for.

The break-even future tax rate is roughly the rate that makes the traditional after-tax value plus any invested tax savings equal the Roth value. If the future tax rate is higher than the current effective tax rate on the contribution, Roth usually improves. If the future rate is lower, traditional often improves. The hard part is that future tax rate is not one number; it can depend on RMDs, Social Security taxation, Medicare IRMAA brackets, state residency, and future legislation.

Why tax savings reinvestment matters

Many Roth-versus-traditional comparisons are unfair because they ignore cash flow. A deductible traditional IRA contribution can create tax savings today. If those savings are spent, the traditional path has less invested outside the IRA. If those savings are invested in a taxable brokerage account, the traditional path gains an extra asset that should be included in the comparison. This is why calculators that include reinvested tax savings can produce different conclusions than simple after-tax-balance calculators.

Suppose a taxpayer contributes $7,500 and is in a 24% current marginal tax bracket. A deductible traditional IRA contribution could free up about $1,800 in federal tax. If that $1,800 is invested every year in a taxable account, it can compound alongside the traditional IRA. At retirement, the traditional IRA is reduced by withdrawal tax, and the taxable account may owe tax on dividends and capital gains. The final comparison is Roth balance versus traditional after-tax balance plus after-tax taxable savings.

The current calculator shows a simple traditional IRA after-tax estimate. It does not yet model invested tax savings. That makes it useful for understanding the withdrawal-tax effect, but incomplete as a full recommendation. When users make real decisions, the key behavioral question is whether they would actually invest the deduction savings. If they would spend it, Roth can look stronger. If they would invest it with discipline, traditional can be more competitive.

Side-by-side scenarios

These scenarios are intentionally simplified. Real households often have employer plans, taxable accounts, HSAs, pensions, Social Security, state taxes, and spouse-specific ages. The point is not to pick the same answer for everyone; it is to identify the variables that move the result. Age 25 cases are dominated by time and future tax uncertainty. Age 45 cases are dominated by current deductions and peak-income tax rates. Age 60 cases are dominated by timing, withdrawal rules, and whether lower-income years create conversion opportunities.

A good scenario table also makes tradeoffs discussable. The age-25 saver may not know future income, but can test whether decades of Roth growth are worth giving up a small current deduction. The age-45 saver may have enough income to make the deduction valuable, but should test whether retirement income from pensions, rental income, or large pre-tax balances will keep future tax rates high. The age-60 saver may have little time for new contributions to compound, but can still value Roth flexibility for later spending, heirs, or managing taxable income in specific retirement years.

Required minimum distribution differences

Traditional IRAs generally become subject to required minimum distributions during retirement. Those distributions can force taxable income even if the account owner would rather leave the money invested. Roth IRAs do not have lifetime required minimum distributions for the original owner. That difference can be valuable for retirees who want more control over taxable income, charitable giving, estate timing, or the order in which accounts are spent.

RMDs matter because they can interact with other retirement tax items. Larger taxable distributions can affect Social Security taxation, Medicare IRMAA brackets, capital-gain tax planning, and state taxable income. A Roth IRA can provide a source of retirement spending that does not raise federal taxable income when distributions are qualified. That does not automatically make Roth better, but it explains why many retirees value having both Roth and pre-tax money available.

Special situations: backdoor, ladder, and mega backdoor Roth

A backdoor Roth IRA is commonly discussed by high-income taxpayers who cannot make direct Roth IRA contributions. The basic idea is to make a nondeductible traditional IRA contribution and then convert it to Roth. The difficult part is not the phrase “backdoor”; it is the tax reporting and the pro-rata rule. Existing pre-tax IRA balances can make a conversion partly taxable, so users should not assume the strategy is tax-free merely because it is common.

A Roth conversion ladder is often used in early-retirement planning. A taxpayer converts pre-tax retirement money into a Roth account in lower-income years, then waits for the relevant timing rules before withdrawing converted amounts. This can help bridge years before traditional retirement age, but it requires careful tracking of taxable conversion income, five-year clocks, cash reserves, and health insurance subsidy effects.

A mega backdoor Roth is different again. It depends on a workplace retirement plan allowing after-tax employee contributions and in-plan Roth conversion or in-service distributions. Not every plan supports it, and contribution ceilings are governed by employer-plan rules, not the ordinary IRA limit. These strategies are powerful in the right circumstances, but they are outside the scope of a simple Roth IRA growth calculator.

State tax considerations

Federal tax gets most of the attention, but state taxes can change the comparison. A worker in a high-tax state today who expects to retire in a no-income-tax state may value a current deduction more than a Roth contribution. The opposite can also happen: a worker in a low-tax state who may retire in a higher-tax state could prefer Roth treatment. State rules are not uniform, and some states treat retirement income differently from federal law.

State tax also matters for conversions and taxable-account side investments. If traditional IRA tax savings are reinvested in a taxable brokerage account, dividends and capital gains may face state taxation along the way. Moving states before retirement can change the future withdrawal tax rate. Because state residency and rules can shift, a robust comparison should test more than one future-tax-rate assumption rather than hard-coding a single number.

One common example is a worker in California, New York, or another high-tax state who expects to retire in a state with no broad wage income tax. In that case, a traditional deduction today can be more valuable than a calculator using only federal rates suggests. The reverse is also possible for someone earning in a low-tax state and retiring somewhere with higher income taxes or different retirement-income rules. State tax should not dominate the decision by itself, but it is large enough that a serious Roth-versus-traditional model should not ignore it.

Decision framework

Start with eligibility. Can you make a direct Roth IRA contribution for the tax year, and is a traditional IRA contribution deductible for your situation? Next, compare current marginal tax rate with a realistic range of future tax rates. Then ask whether you would invest traditional IRA tax savings or spend them. Finally, consider non-math factors: RMD control, estate goals, liquidity, early-retirement timelines, and tax diversification.

Roth may deserve priority when current tax rates are low, the time horizon is long, future rates are uncertain or likely higher, and tax-free retirement income has strategic value. Traditional may deserve priority when current rates are high, the deduction is available, future taxable income is expected to be lower, and the saver will invest the tax savings. Splitting contributions between Roth and pre-tax accounts can also be rational because the future is uncertain.

Use the calculator below for the growth side of the question, then treat tax treatment as a separate planning layer. The calculator can show how time and return assumptions affect a Roth-style projection. It cannot tell you your filing status, future tax law, state residency, or whether a specific deduction or conversion strategy is correct.

A practical checklist is: first confirm whether a Roth IRA contribution is allowed; second confirm whether a traditional IRA deduction is available; third compare current and future tax-rate ranges; fourth decide whether tax savings would be invested; fifth test the result under lower and higher investment returns; sixth document why the chosen account type fits the household's broader plan. If the decision is close, splitting retirement savings between Roth and pre-tax accounts may be more resilient than trying to predict one perfect future tax bracket.

This is also where employer plans matter. If a 401(k) offers a strong match, capturing that match may rank ahead of either IRA choice. If a workplace Roth 401(k) is available, the contribution limit and payroll mechanics differ from a Roth IRA. If a high-deductible health plan makes an HSA available, the HSA may compete for the next savings dollar. Roth versus traditional IRA is an important decision, but it should sit inside the full retirement-account stack rather than being evaluated in isolation.

Sources

• IRS IR-2025-111
• IRS Publication 590-A
• IRS Publication 590-B
• IRS Roth IRAs overview