Roth IRA Calculator

Background.

A Roth IRA calculator projects what your account will be worth at retirement, and — unlike almost every other retirement calculator — it also has to model whether the IRS will let you contribute the amount you want to in the first place. Roth IRAs are one of the few retirement accounts subject to an income-based eligibility phase-out: earn too much in a given year, and your allowed contribution shrinks, then disappears entirely. This calculator handles both halves of the problem using the 2026 IRS figures, verified directly from irs.gov on July 27, 2026: a $7,500 annual contribution limit ($8,600 if you are 50 or older, thanks to the $1,100 catch-up contribution), and a Modified Adjusted Gross Income phase-out that begins at $153,000 for Single filers ($242,000 for Married Filing Jointly) and eliminates eligibility entirely at $168,000 ($252,000 for joint filers).

The headline feature of a Roth IRA — and the reason it's worth the extra eligibility complexity — is that qualified withdrawals in retirement are completely tax-free, not merely tax-deferred. Contribute after-tax dollars now, and neither your contributions nor any of the investment growth on top of them is ever taxed again, provided you meet the five-year holding period and are at least 59½ when you withdraw. Compare that to a traditional 401(k) or traditional IRA, where every withdrawal in retirement is taxed as ordinary income — Quanta's 401(k) calculator covers that side of the comparison in detail. The Roth structure is a bet that your tax rate in retirement will be the same or higher than it is today; if that's true, paying tax on the smaller number (your contribution) now rather than the larger number (your contribution plus decades of growth) later is the better trade.

To use this calculator, enter your current Roth IRA balance, your age (which determines whether the $1,100 catch-up applies), how much you plan to contribute each year, your expected annual return, how many years until you plan to withdraw, your filing status, and your Modified AGI. The calculator first works out your actual IRS-allowed contribution ceiling for 2026 — factoring in both the catch-up and the phase-out — then projects your balance forward using the standard ordinary-annuity growth formula, the same one used across Quanta's savings-goal and future-value calculators, applied to whichever contribution amount is actually allowed (which may be less than what you asked for, if your income phases you out).

This version of the calculator supports Single (including Head of Household, per how the IRS treats this specific phase-out) and Married Filing Jointly filing statuses. Married Filing Separately is not supported — its phase-out range is a flat, un-indexed $0 to $10,000 window that doesn't map cleanly onto the same proportional-reduction UI used for the other two statuses, and it affects a small minority of filers. The IRS's own Worksheet 2-2 additionally rounds the reduced contribution up to the nearest $10 and applies a $200 floor on any partial contribution; that exact rounding rule could not be confirmed from a machine-readable IRS source in this session, so this calculator reports the continuous, unrounded version of the reduction formula instead — a conservative simplification disclosed in the FAQ below, not a guessed number.

Run the numbers below to see both halves of the Roth IRA story at once: how much you're actually allowed to put in this year, and what that contribution stream, left alone to compound tax-free, is worth by the time you retire.

What is roth ira calculator?

A Roth IRA (Individual Retirement Arrangement) is a personal retirement account funded with after-tax dollars, in exchange for which the IRS never taxes the account again — not the original contributions, and not any of the investment growth — provided withdrawals are "qualified": the account has been open at least five years and the owner is at least 59½ (with limited exceptions for disability, a first home purchase, and a few other cases). This is the core distinction from a traditional IRA or a traditional 401(k), both of which are funded pre-tax and taxed as ordinary income on withdrawal. Because Roth IRAs are meant to help middle- and lower-income savers rather than substitute for employer plans at the top of the income scale, the IRS caps who can contribute directly: for 2026, the ability to contribute phases out between $153,000 and $168,000 of Modified Adjusted Gross Income for Single filers, and between $242,000 and $252,000 for Married Filing Jointly filers. Within the phase-out range, the allowed contribution shrinks proportionally to how far into the range your MAGI falls; above the upper threshold, direct contributions are not allowed at all (though a "backdoor Roth" conversion strategy exists for high earners, using a nondeductible traditional IRA contribution converted to Roth — not modeled by this calculator). The base contribution limit for 2026 is $7,500, with an additional $1,100 catch-up contribution available starting the year you turn 50, for a total of $8,600.

How to use this calculator.

1. 01Enter your current Roth IRA balance.
2. 02Enter your age — 50 or older unlocks the 2026 catch-up contribution.
3. 03Enter how much you plan to contribute annually. The calculator will cap this at your actual IRS-allowed limit if your income phases you out of the full amount.
4. 04Enter your expected annual return, e.g. 7% for a stock-heavy long-term portfolio.
5. 05Enter the number of years until you plan to withdraw.
6. 06Select your filing status: Single/Head of Household or Married Filing Jointly.
7. 07Enter your Modified AGI. This drives the income phase-out calculation.
8. 08Compare the Max IRS-Allowed Contribution against the Contribution Used in Projection — if they differ, your income is phasing you out of your full desired contribution — then read the Projected Balance and Tax-Free Growth as your bottom line.

The formula.

Reviewed on 2026-07-27 against the IRS's own published 2026 figures. The calculator works in two stages. First, it establishes your base 2026 contribution limit: $7,500, or $8,600 if you are 50 or older (the extra $1,100 is the IRS catch-up contribution). Second, it applies the Modified AGI phase-out using the IRS's own five-step reduction method: if your MAGI is at or below the lower threshold ($153,000 single, $242,000 joint), you get the full base limit; if it's at or above the upper threshold ($168,000 single, $252,000 joint), your allowed contribution is zero; in between, the allowed contribution shrinks proportionally — specifically, base limit minus (base limit times the fraction of the way your MAGI sits into the phase-out range). The phase-out range width is $15,000 for Single/Head of Household and $10,000 for Married Filing Jointly, matching the IRS's own divisors. Whatever contribution you asked for is then capped at this calculated ceiling — the smaller of the two numbers is what actually gets compounded forward.

The growth projection itself uses the standard ordinary-annuity formula: your current balance grows by the compounding factor (1 + r)^n, where r is your annual return as a decimal and n is the number of years, while your allowed annual contribution — assumed to be deposited at the end of each year — grows through the annuity factor ((1+r)^n − 1) / r. When your expected return is exactly 0%, the formula falls back to simple addition (contribution times years) rather than dividing by zero. Total contributions is just the allowed contribution multiplied by the number of years, and tax-free growth is whatever is left over once you subtract your starting balance and your total contributions from the final projected balance — every dollar of which is the tax-free benefit of the Roth structure.

One disclosed simplification: the official IRS worksheet (Publication 590-A, Worksheet 2-2) rounds the reduced contribution up to the next $10 and imposes a $200 minimum on any non-zero partial contribution. This calculator reports the continuous, unrounded reduction instead, because the exact wording of that rounding step could not be confirmed from a machine-readable IRS source in this session — the reported figure will be within a few dollars of the IRS's own rounded worksheet result, never overstated in your favor.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Internal Revenue Service (2025). "401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500." IRS Newsroom.
2. [2]Internal Revenue Service. "Amount of Roth IRA Contributions That You Can Make."
3. [3]Internal Revenue Service (2025). Notice 2025-67: 2026 Amounts Relating to Retirement Plans and IRAs.
4. [4]Internal Revenue Service. Publication 590-A: Contributions to Individual Retirement Arrangements (IRAs).
5. [5]Internal Revenue Service. Publication 590-B: Distributions from Individual Retirement Arrangements (IRAs).