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How a Roth IRA Works: Contributions, Growth, and Withdrawals

By Felix Thorpe · Retirement Accounts Writer

How a Roth IRA Builds Your Retirement Savings

A Roth IRA is a retirement account where you contribute money that has already been taxed, and then the account grows tax-free. When you withdraw money in retirement, you pay no federal income tax on the earnings or the contributions you put in. This is the opposite of a traditional IRA, where contributions may be tax-deductible now but withdrawals are taxed later.

The account itself is opened at a bank, brokerage, or investment company — not through your employer. You control what investments go inside it: stocks, bonds, mutual funds, or simply cash. The money grows year after year, and as long as you follow the withdrawal rules, that growth stays yours tax-free.

Key Takeaways

  • You contribute after-tax dollars to a Roth IRA, meaning you cannot deduct the contribution from your income taxes that year.
  • Your contributions and earnings grow tax-free inside the account, and you owe no federal tax when you withdraw them in retirement.
  • You can withdraw your contributions (the money you put in) at any time without penalty, but earnings have strict withdrawal rules tied to age and account age.
  • Annual contribution limits are set by the IRS and change most years; for 2024 the limit is $7,000 if you are under 50, or $8,000 if you are 50 or older.
  • Income limits determine whether you can contribute directly to a Roth IRA, and these limits phase out at higher earnings levels.

Contribution Limits and Income Thresholds

The IRS sets an annual limit on how much you can put into a Roth IRA each year. That limit changes periodically. For 2024, you can contribute up to $7,000 if you are under age 50, or $8,000 if you are 50 or older (the extra $1,000 is called a catch-up contribution). The limit for 2025 may differ, so check the IRS website or your account provider before you contribute.

Your ability to contribute directly to a Roth IRA also depends on your income. The IRS phases out your contribution limit as your modified adjusted gross income (MAGI) rises. The income thresholds vary by filing status — single filers face different limits than married couples filing jointly — and they change each year. If your income exceeds the phase-out range, you cannot contribute directly to a Roth IRA, though a backdoor Roth conversion may still be an option.

You can contribute to a Roth IRA only if you have earned income from work. You cannot fund it with investment returns, inheritance, or other unearned money. If you have no income in a given year, you cannot contribute that year.

How Tax-Free Growth Works Inside the Account

Once money is inside your Roth IRA, it grows without triggering any annual tax bill. If you own stocks that pay dividends, you do not owe tax on those dividends. If you sell an investment inside the account at a profit, that gain is not taxed. This is different from holding the same investments in a regular taxable brokerage account, where you would owe tax each year on dividends and capital gains.

The tax-free growth compounds over decades. A $7,000 contribution at age 25 that grows at an average annual rate of 7 percent will be worth roughly $147,000 by age 65 — and you will owe no tax on any of that growth. The longer the money stays in the account, the more powerful this tax-free compounding becomes.

Withdrawal Rules for Contributions vs. Earnings

The IRS treats contributions and earnings differently when you withdraw money. Your contributions — the dollars you actually put in — can be withdrawn at any time, for any reason, with no tax and no penalty. If you contributed $50,000 over ten years and need to pull out $10,000, you can do so without consequence.

Your earnings — the investment gains inside the account — have stricter rules. To withdraw earnings tax-free and penalty-free, you must meet two conditions: you must be at least 59½ years old, and the account must have been open for at least five tax years. If you withdraw earnings before age 59½, or before the five-year mark, you will owe federal income tax on those earnings plus a 10 percent early withdrawal penalty (with some exceptions, such as disability or first-time home purchase up to $10,000).

The five-year rule applies to the account itself, not to each contribution. If you opened your first Roth IRA in 2020, all Roth IRAs you own satisfy the five-year rule starting in 2025, even if you opened a second Roth IRA in 2023.

The Backdoor Roth Conversion for High Earners

If your income is too high to contribute directly to a Roth IRA, you may be able to use a backdoor Roth conversion. This strategy involves contributing money to a traditional IRA (which has no income limit) and then converting it to a Roth IRA. The conversion itself is taxable in the year you do it, but the money then grows tax-free in the Roth.

A backdoor Roth works best when you have little or no balance in any traditional, SEP, or SIMPLE IRA accounts. If you do have a balance in a traditional IRA, the conversion becomes complicated because the IRS applies a pro-rata rule: a portion of the conversion will be taxable based on the ratio of pre-tax money to after-tax money across all your IRAs. Consult a tax professional before attempting a backdoor Roth if you have existing IRA balances.

Required Minimum Distributions and Roth IRAs

Unlike a traditional IRA, a Roth IRA has no required minimum distributions (RMDs) during your lifetime. You never have to withdraw money from a Roth IRA just because you reach a certain age. This makes a Roth IRA a powerful tool for leaving money to heirs, since the account can keep growing tax-free for decades.

Your beneficiaries will have to withdraw the money after you die, but they will still owe no federal income tax on the earnings (though the rules for inherited Roth IRAs changed in 2023 and now require most non-spouse beneficiaries to empty the account within ten years). This makes a Roth IRA an attractive way to pass wealth to the next generation.

When a Roth IRA Makes Sense for Your Situation

A Roth IRA is most valuable if you expect to be in a higher tax bracket in retirement than you are now, or if you simply want to lock in today's tax rates. If you are young and earning a modest income, a Roth IRA lets you pay tax at a low rate now and avoid tax on decades of growth. If you are self-employed or have variable income, a Roth IRA offers flexibility because you can withdraw contributions if cash flow tightens.

A Roth IRA is less attractive if you need a tax deduction this year (a traditional IRA may help more), or if you are already in a very high tax bracket and expect to be in a lower one in retirement. It is also less useful if you have little earned income, since contribution limits are tied to what you earn.

Many people benefit from holding both a Roth IRA and a traditional IRA or 401(k), splitting their retirement savings between tax-now and tax-later accounts. This approach, called tax diversification, gives you flexibility in retirement to withdraw from whichever account makes sense for your tax situation that year.

Frequently Asked Questions

Can I withdraw my contributions before retirement without penalty?

Yes. You can withdraw contributions you have made to a Roth IRA at any time, for any reason, with no tax and no penalty. Only earnings are subject to the age and five-year holding period rules. Keep records of how much you contributed versus how much you earned, since the IRS uses the pro-rata rule to determine which portion of a withdrawal is a contribution and which is earnings.

What happens if I exceed the annual contribution limit?

If you contribute more than the IRS limit in a single year, the excess is considered an excess contribution. You will owe a 6 percent excise tax on the excess amount each year it remains in the account. You can correct this by withdrawing the excess and any earnings on it before your tax return deadline (including extensions). Consult a tax professional if this happens, since the rules for correcting excess contributions are detailed.

Can I have multiple Roth IRAs?

Yes, you can open as many Roth IRAs as you want. However, your total contributions across all Roth IRAs in a single year cannot exceed the annual limit. If you have three Roth IRAs and contribute $3,000 to each, you have exceeded the limit and owe the 6 percent excise tax on the excess $2,000. Track your total contributions across all accounts.

What is the difference between a Roth IRA and a Roth 401(k)?

A Roth 401(k) is offered through your employer and has much higher contribution limits (up to $69,000 in 2024). A Roth IRA is opened on your own and has lower limits ($7,000 in 2024). A Roth 401(k) requires minimum distributions at age 73, while a Roth IRA does not. Both grow tax-free and allow tax-free withdrawals in retirement if rules are met.

Can I convert a traditional IRA to a Roth IRA?

Yes. A Roth conversion involves moving money from a traditional IRA to a Roth IRA. The amount you convert is taxable income in the year of the conversion, but the money then grows tax-free in the Roth. There is no income limit on conversions, so high earners can use this strategy. Be aware of the pro-rata rule if you have multiple IRA accounts.