Roth IRA Calculator: Project Your Tax-Free Growth

Roth IRA Calculator: How Much Your Tax-Free Retirement Savings Could Grow

Quick summary: A Roth IRA calculator projects how your contributions could grow tax-free over time using the compound interest formula, factoring in the 2026 contribution limit of $7,500 ($8,600 if you’re 50 or older) and IRS income phase-out rules. Unlike a traditional IRA, a Roth IRA is funded with after-tax dollars, so qualified withdrawals in retirement — including all the growth — come out completely tax-free.

Few retirement accounts get talked about as much as the Roth IRA, and for good reason: the tax-free growth it offers can add up to a genuinely large difference over a multi-decade career. A Roth IRA calculator helps you see exactly how that growth compounds over time, while also checking whether you’re even eligible to contribute based on your income. This guide covers the compound growth formula behind a Roth IRA calculator, the current 2026 contribution and income limits, and several fully worked examples.

What Is a Roth IRA Calculator?

A Roth IRA calculator projects the future value of your retirement contributions by applying compound interest to your annual deposits over a chosen number of years. Because a Roth IRA is funded with money you’ve already paid taxes on, qualified withdrawals in retirement — both your original contributions and all the investment growth — are completely tax-free, which is the core appeal of the account (irs.gov).

2026 Roth IRA Contribution Limits

According to the IRS’s official 2026 cost-of-living adjustment announcement, the annual IRA contribution limit — which applies to traditional and Roth IRAs combined — increased to $7,500 for 2026, up from $7,000 in 2025. The catch-up contribution limit for individuals age 50 and over also increased, from $1,000 to $1,100, bringing the total contribution limit for those 50 and older to $8,600 (irs.gov).

This limit is shared between account types — you can’t contribute $7,500 to a Roth IRA and another $7,500 to a traditional IRA in the same year; the $7,500 (or $8,600) cap applies across both combined.

2026 Roth IRA Income Phase-Out Limits

Your eligibility to contribute directly to a Roth IRA is based on your Modified Adjusted Gross Income (MAGI), and it phases out gradually rather than cutting off all at once. For 2026:

Filing Status	Full Contribution Below	Phases Out Between	No Direct Contribution Above
Single / Head of Household	$153,000	$153,000–$168,000	$168,000
Married Filing Jointly	$242,000	$242,000–$252,000	$252,000

(finance.yahoo.com, citing IRS Notice 2025-67)

If your MAGI exceeds these thresholds, you may still be able to fund a Roth IRA indirectly through a backdoor Roth conversion — contributing to a traditional IRA (which has no income limit for non-deductible contributions) and then converting those funds to a Roth IRA.

Calculating a Reduced Contribution in the Phase-Out Range

If your MAGI falls inside the phase-out range, the IRS uses a specific formula to calculate your reduced contribution limit:

Start with your MAGI
Subtract the phase-out floor for your filing status ($153,000 single / $242,000 married filing jointly)
Divide the result by the phase-out range width ($15,000 for single filers, $10,000 for married filing jointly)
Multiply that fraction by the full contribution limit ($7,500 or $8,600)

(401kretirementcalc.com; irs.gov)

The Roth IRA Growth Formula

Once your contribution eligibility is confirmed, a Roth IRA calculator projects growth using the standard compound interest with recurring contributions formula:

Future Value = P × [((1 + r)ⁿ − 1) ÷ r] × (1 + r)

Where:

P = your annual (or periodic) contribution
r = your expected annual rate of return
n = number of years until retirement

This formula assumes contributions are made at the start of each period and compounds them annually, though real-world calculators typically allow monthly compounding for more precision.

Worked Examples

Example 1: Starting early, modest contributions

A 25-year-old contributes $7,500/year to a Roth IRA, earning an average 7% annual return, until retiring at 65 (40 years).

Using the compound growth formula, this comes out to approximately $1,570,000 at retirement — all of which can be withdrawn completely tax-free, assuming the account has been open at least 5 years and the account holder is 59½ or older.

Example 2: Starting later, with catch-up contributions

A 50-year-old begins contributing the maximum $8,600/year (including the $1,100 catch-up), earning 6% annual return, until retiring at 65 (15 years).

Future Value ≈ $8,600 × [((1.06)¹⁵ − 1) ÷ 0.06] × 1.06 ≈ $212,700

This example illustrates why starting early matters so much — even with a higher annual contribution, 15 years of compounding produces a dramatically smaller total than 40 years, due to how much less time the money has to compound.

Example 3: Checking phase-out eligibility

A single filer has a MAGI of $160,000 in 2026 — inside the $153,000–$168,000 phase-out range.

Step 1: $160,000 − $153,000 = $7,000 Step 2: $7,000 ÷ $15,000 = 0.4667 Step 3: Remaining contribution room = (1 − 0.4667) × $7,500 = ≈ $4,000 (rounded to the nearest $10 in actual IRS calculations)

This filer can still contribute roughly $4,000 to a Roth IRA in 2026, even though they’re above the full-contribution threshold.

Example 4: A married couple above the limit

A married couple filing jointly has a combined MAGI of $260,000 — above the $252,000 ceiling.

Result: Neither spouse can make a direct Roth IRA contribution for 2026. Their remaining option is the backdoor Roth strategy — contributing to a traditional IRA, then converting those funds to a Roth IRA.

Why the “Backdoor Roth” Comes With a Catch: The Pro-Rata Rule

If you have existing pre-tax funds in a traditional IRA, converting to a Roth isn’t as simple as converting only your new, non-deductible contribution. The pro-rata rule requires that any conversion be treated as coming proportionally from all of your traditional IRA funds — both pre-tax and after-tax — not just the portion you intended to convert (ira.com; 401kretirementcalc.com).

Example: If you have $95,000 in pre-tax traditional IRA funds and contribute an additional $7,500 as a non-deductible contribution, only about 7.3% of any conversion would be tax-free, since that’s the after-tax portion’s share of your total traditional IRA balance (401kretirementcalc.com).

Roth IRA vs. Traditional IRA: The Core Trade-Off

The fundamental difference comes down to when you pay taxes:

Roth IRA — contributions are made with after-tax dollars (no upfront deduction), but qualified withdrawals in retirement, including all growth, are tax-free
Traditional IRA — contributions may be tax-deductible now, but withdrawals in retirement are taxed as ordinary income

Generally, a Roth IRA tends to favor people who expect to be in a higher tax bracket in retirement than they are now — such as younger workers early in their careers — since paying tax on contributions at today’s (lower) rate can be more advantageous than paying tax on a much larger balance later.

Common Roth IRA Mistakes

Over-contributing beyond the limit or your phase-out allowance. Excess contributions are subject to a 6% penalty per year until corrected (ira.com).
Contributing without sufficient earned income. A Roth IRA requires earned income — wages or self-employment income — at least equal to your contribution; investment income, Social Security, and pensions don’t count (firstcard.app).
Forgetting the 5-year rule. Even after age 59½, your Roth IRA account generally needs to have been open at least 5 years for earnings withdrawals to be fully tax-free and penalty-free.
Ignoring the pro-rata rule on backdoor conversions, which can make part of a “tax-free” conversion unexpectedly taxable if other traditional IRA balances exist.
Using taxable income instead of MAGI when checking phase-out eligibility — these are calculated differently (taxcalchub.com).

FAQs

What is the 2026 Roth IRA contribution limit?

The 2026 Roth IRA contribution limit is $7,500 for those under 50, and $8,600 for those 50 and older (including the $1,100 catch-up contribution), according to IRS Notice 2025-67.

What income disqualifies you from contributing to a Roth IRA in 2026?

For 2026, single filers with a MAGI above $168,000 and married couples filing jointly with a MAGI above $252,000 cannot make a direct Roth IRA contribution, though the backdoor Roth strategy may still be available.

Are Roth IRA withdrawals really tax-free?

Qualified withdrawals — meaning the account has been open at least 5 years and you’re 59½ or older (with some exceptions) — are completely tax-free, covering both your original contributions and all investment growth.

What is the backdoor Roth IRA strategy?

It’s a method for high earners who exceed the income limits to still fund a Roth IRA: contributing to a traditional IRA (which has no income limit for non-deductible contributions) and then converting those funds to a Roth IRA.

Does a Roth IRA calculator account for the pro-rata rule?

Basic growth-projection calculators typically don’t — the pro-rata rule only applies to backdoor Roth conversions involving existing pre-tax traditional IRA balances, and calculating its exact impact usually requires a separate, more detailed calculation.

Related Calculators

Conclusion

A Roth IRA calculator turns the powerful but sometimes confusing rules around tax-free retirement growth into a concrete number you can actually plan around — combining the 2026 contribution limit of $7,500 (or $8,600 for those 50+), the IRS income phase-out thresholds, and standard compound interest math. Whether you’re just starting your first Roth IRA in your twenties or navigating a backdoor conversion because you’ve exceeded the income limits, running your numbers through a Roth IRA calculator gives you a clearer, more realistic picture of what your tax-free retirement savings could actually become.