How Traditional and Roth IRA Tax Treatment Differs

Individual Retirement Accounts come in two principal forms — Traditional and Roth — and the Internal Revenue Code treats them as mirror images of each other in one critical respect: the point at which the federal government collects its tax. In a Traditional IRA, a deduction is available at contribution (subject to income and workplace-plan conditions), growth accumulates on a tax-deferred basis, and every dollar withdrawn in retirement is included in ordinary income. In a Roth IRA, contributions are made with after-tax dollars, no deduction is available, but qualified distributions — including all accumulated earnings — are excluded from gross income entirely.

This piece covers the mechanics of how each account type is taxed at three distinct stages: contribution, accumulation, and distribution. It also covers how the IRS enforces the boundary between the two types through basis tracking, ordering rules, and the qualified-distribution test.

The Tax Timing Split: Contribution, Growth, and Distribution

Traditional IRA — contribution stage. A contribution to a Traditional IRA may be fully deductible, partially deductible, or non-deductible depending on whether the account owner (or a spouse) is covered by a workplace retirement plan and on the household's modified adjusted gross income (MAGI). The IRS publishes the applicable MAGI phase-out ranges each year, and they adjust for inflation. When a contribution is non-deductible — because income exceeds the phase-out — the account owner establishes "basis" in the IRA, which must be tracked on IRS Form 8606. Failing to track basis causes those after-tax dollars to be taxed a second time at withdrawal.

Traditional IRA — distribution stage. Withdrawals from a Traditional IRA are included in ordinary income in the year received. Because the pre-tax dollars and any deferred earnings have never been taxed, the full distribution is subject to income tax at the account owner's marginal rate at the time of withdrawal. The only exception is the pro-rata recovery of any non-deductible basis, calculated using Form 8606 each year a distribution occurs. Additionally, distributions taken before age 59½ are generally subject to a 10 percent additional tax under IRC § 72(t), with specific statutory exceptions. Traditional IRAs are also subject to required minimum distributions (RMDs), which begin at the age specified under current law — a mechanism described separately in how required minimum distributions are actually calculated.

Roth IRA — contribution stage. Contributions to a Roth IRA are made with after-tax dollars and are never deductible. The ability to contribute directly to a Roth IRA phases out at MAGI thresholds that the IRS adjusts annually. Above the upper threshold, direct contributions are not permitted. The annual contribution limit is the same dollar ceiling that applies to Traditional IRAs — the two account types share a combined limit, not separate ones. For 2024, the combined limit is $7,000, with a $1,000 catch-up for those age 50 and older, per IRS Publication 590-A.

Roth IRA — distribution stage. Roth IRA distributions follow a specific ordering rule set out in IRC § 408A and the related Treasury regulations. Contributions (basis) are always treated as distributed first, and because those dollars were already taxed, they come out tax-free and penalty-free at any time. Earnings are distributed last. For earnings to be distributed tax-free and penalty-free, the distribution must be "qualified" — meaning the account must have been open for at least five tax years (the five-year rule), and the distribution must occur after the account owner reaches age 59½, becomes disabled, dies, or uses up to $10,000 for a first-time home purchase. If the distribution is not qualified, the earnings portion is included in ordinary income and may be subject to the 10 percent additional tax.

The five-year rule in detail. The Roth five-year clock starts on January 1 of the first tax year for which a Roth IRA contribution is made. It does not restart for each new contribution. A separate five-year clock applies to each Roth conversion — amounts converted from a Traditional IRA or 401(k) to a Roth IRA must remain in the account for five years before the converted principal can be withdrawn without the 10 percent additional tax (if the account owner is under 59½). This means a single Roth IRA account can simultaneously contain contribution basis, multiple conversion layers each with their own clock, and earnings — all governed by the ordering rules.

Roth IRA and RMDs. Unlike Traditional IRAs, Roth IRAs are not subject to required minimum distributions during the account owner's lifetime under current law. This structural difference affects how account balances accumulate over extended periods and has downstream implications for income calculations — including the provisional income formula used to determine how much of a Social Security benefit is subject to federal tax, since Roth distributions are generally excluded from that calculation.

Who Administers the Accounts and Enforces the Rules

Both Traditional and Roth IRAs are held at a custodian — typically a bank, a brokerage, or a similar financial institution acting in a custodial role. The custodian holds the assets, executes transactions within the account, and issues IRS Form 5498 each year to report contributions and the fair market value of the account. The custodian also issues Form 1099-R when a distribution occurs, coding the distribution box to indicate whether it is early, normal, a Roth distribution, or a conversion.

The custodian does not determine the tax treatment of any given distribution — that determination falls to the account owner and, ultimately, to the IRS. The account owner is responsible for filing Form 8606 to track non-deductible Traditional IRA basis and to report Roth IRA distributions and conversions. If Form 8606 is not filed when required, the IRS has no record of after-tax basis, and the account owner bears the burden of proving it.

The IRS enforces contribution limits, the additional 10 percent tax on early distributions, and the qualified-distribution requirements through the income tax filing process. Excess contributions — amounts above the annual limit — are subject to a 6 percent excise tax for each year the excess remains in the account, reported on Form 5329.

When a Roth conversion occurs, the converting institution reports the taxable amount on Form 1099-R with the appropriate distribution code, and the account owner reports the conversion income on their federal return. The new Roth custodian — which may or may not be the same institution — reports the incoming amount on Form 5498. The two forms together create the paper trail the IRS uses to verify that conversion income was reported.

Where the Two Structures Produce Unexpected or Misread Results

The pro-rata rule on Traditional IRA distributions. A common misread occurs when an account owner has both deductible and non-deductible amounts in a Traditional IRA (or across multiple Traditional IRAs, which the IRS aggregates). The assumption is sometimes made that the non-deductible basis can be withdrawn first, tax-free, leaving only the pre-tax dollars for later. The IRS does not permit this. Every distribution is treated as coming proportionally from pre-tax and after-tax amounts across all Traditional IRAs held by the same owner. This pro-rata rule frequently produces a taxable result larger than the account owner anticipated.

The Roth conversion ladder and the five-year clock. Roth conversions are sometimes treated as equivalent to original Roth contributions for withdrawal purposes. They are not. Each conversion carries its own five-year holding requirement for the converted principal to be withdrawn before age 59½ without the 10 percent additional tax. Account owners who perform multiple annual conversions and then take distributions before 59½ may find that some conversion layers are still within their five-year window, making the principal of those layers subject to the penalty even though earnings are not yet in play.

Income effects of Roth conversions. A Roth conversion is a taxable event in the year it occurs — the converted amount is included in ordinary income. A large conversion can push MAGI into a higher bracket, trigger the net investment income tax, or affect income-tested programs. One such effect involves how Medicare Part B premiums scale with income: premiums are determined by MAGI from two years prior, so a conversion executed in one year can increase premiums two years later without any change in the account owner's underlying financial position in the premium year.

The aggregation rule and rollover IRAs. When a pre-tax 401(k) balance is rolled into a Traditional IRA, it becomes part of the same pool the IRS aggregates for the pro-rata rule. An account owner who previously held only non-deductible IRA basis and then adds a large pre-tax rollover will find that the ratio of taxable to non-taxable amounts in all future distributions shifts substantially — often in a direction that increases the taxable portion of each withdrawal.

State tax treatment. Federal tax treatment of IRA distributions does not automatically determine state tax treatment. Some states follow federal law; others do not conform to the Roth exclusion, tax early distributions differently, or impose their own age-based exemptions. The federal mechanics described here apply only to federal income tax.

What Account Statements and IRS Forms Show — and What They Do Not

Form 5498, issued by the custodian each year by May 31, reports the dollar amount of contributions made to a Traditional or Roth IRA for the prior tax year, the fair market value of the account as of December 31, and whether any rollover or conversion was received. It does not distinguish between deductible and non-deductible contributions — that determination and tracking is the account owner's responsibility via Form 8606.

Form 1099-R, issued when a distribution or conversion occurs, reports the gross distribution amount, the taxable amount (if the custodian can determine it), and a distribution code in Box 7 that indicates the nature of the distribution. For Roth IRAs, the custodian often cannot determine whether a distribution is qualified — it does not know when the five-year clock started or whether the account owner meets the age or other qualifying conditions — so the taxable amount box may be left blank or marked as "unknown." The account owner must make that determination on their own return.

Account statements from the custodian show the current market value of holdings and transaction history. They do not show the account's tax basis, the split between contributed and converted amounts, or the applicable five-year clocks. For Traditional IRAs with non-deductible contributions, the cumulative basis figure exists only in the account owner's own records and in the Form 8606 filings on record with the IRS.

The IRS transcript for a given tax year will reflect any Form 8606 filed, but it will not proactively alert an account owner that basis is being lost through non-filing. The absence of a Form 8606 is not automatically flagged as an error in the year it is missed — the consequence typically surfaces only when a distribution occurs and no basis record exists to offset the taxable amount.

The Traditional and Roth IRA structures represent two legislative answers to the same question — when should retirement savings be taxed — and the machinery that implements each answer runs through contribution limits, basis tracking forms, ordering rules, and qualified-distribution tests that operate independently of the account's investment performance or market value.

Note: This explains how a retirement system works. It is not financial, tax, or legal advice, it is not specific to any individual's retirement, and it is not a substitute for a licensed financial, tax, or legal professional. Rules, ages, and dollar limits change by year — check the cited sources.