Tax-Deferred Account

Tax deferral moves the tax on your savings from the year you earn the money to the year you take it out. In a traditional 401(k) or IRA, what you contribute is excluded or deducted from this year’s taxable income. Inside the account, dividends, interest and gains build up with no yearly tax, which is what tax-deferred growth means. When you withdraw, every dollar that was never taxed, contributions and growth alike, is taxed as ordinary income, even growth that would have qualified for lower capital gains rates in a taxable account.

It helps to think of a tax-deferred balance as jointly owned. At a 22% tax rate, roughly 22 cents of each dollar belongs to the government; you simply control when it collects. Its share grows at the same rate as yours, which is why deferral by itself does not beat paying the tax up front in a Roth. What it does beat is a taxable account, where yearly tax on dividends and gains slows compounding.

The real payoff is rate arbitrage: deducting contributions at a high marginal rate while working and withdrawing at a lower rate in retirement. The formula below measures that gap directly.

Tax-deferred usually means a traditional retirement account, but several other products postpone tax on their earnings. They differ in whether contributions are deductible and in how withdrawals are ordered and penalized. The common thread is that earnings are taxed only when you take them, and at ordinary income rates rather than capital gains rates. Whether the money going in was deducted decides how much of each withdrawal is taxable: deducted contributions come out taxed, while after-tax contributions, known as basis, come back tax-free.

Deferral beats paying the tax up front in a Roth account only when the rate on the way out is lower than the rate saved on the way in. Taxable accounts give no break at all but impose no restrictions; the table below lines up all three.

The hard part is predicting your later rate, and several things can push it higher than expected. Required withdrawals add income whether you need it or not. Up to 85% of Social Security benefits can become taxable as other income rises, the jump known as the tax torpedo. Higher income can trigger Medicare IRMAA surcharges two years later. A surviving spouse usually files as a single taxpayer after the year of death, with narrower brackets, the widow’s penalty. And a move to a state with a higher income tax raises the cost of every withdrawal.

Rates can also fall: many retirees spend less than they earned, and a move to a state with no income tax removes a layer entirely. Because nobody knows future tax law, many planners keep some money in each bucket, a hedge called tax diversification.

Because the government is waiting to collect, tax-deferred retirement accounts come with rules that discourage taking the money early and eventually force it out. The deferred tax also survives you and passes to your heirs. The rules below apply to traditional 401(k)s, 403(b)s and IRAs alike, with the differences noted, and they are part of why a traditional balance is worth less after tax than a Roth balance of the same size.

A big traditional balance is good news with a tax bill attached, and the years between retirement and the first required distribution are often the best time to shrink that bill. With wages gone and Social Security possibly delayed, taxable income can be unusually low. Filling the low brackets in those years, either by withdrawing to spend or by moving money through a Roth conversion, pays tax at rates that may never be this low again.

From age 70½, a qualified charitable distribution can send up to $111,000 in 2026 straight from an IRA to charity without counting as income, and it counts toward any required distribution. Drawing from tax-deferred, Roth and taxable accounts in a planned mix, rather than emptying one before the next, can keep taxable income steadier from year to year; choosing that mix is the job of a tax-efficient withdrawal strategy.