How to Calculate Your Roth IRA Contribution in 2026

What the limit is

A Roth IRA lets your money grow tax-free, but the IRS caps how much you can put in each year — and the cap depends on your income. For 2026 the limit is $7,500 if you are under 50 and $8,600 if you are 50 or older. The limit is full below the phase-out, shrinks proportionally inside it, and is $0 above it. The calculation is four steps: find your full limit, find your phase-out range, work out the reduced limit, and compare it with what you planned. This guide works through all four with real numbers.

Step 1: Find your full limit

Your age sets the starting point. If you are under 50 in 2026, your full limit is $7,500. If you are 50 or older — the catch-up starts in the year you turn 50 — it is $8,600, which is $7,500 plus $1,100. At age 50 exactly the limit is $8,600; at age 49 it is $7,500. Age matters nowhere else: the phase-out ranges do not change with age.

Step 2: Find your phase-out range

Your filing status sets the income range over which the limit shrinks. Single and head of household: $153,000 to $168,000. Married filing jointly: $242,000 to $252,000. Married filing separately, if you lived with your spouse at any time during the year: $0 to $10,000 — the narrowest range. If you lived apart from your spouse all year, the IRS lets you use the single range instead. Below the range, the full limit applies. Above it, the limit is $0.

Step 3: Work out the reduced limit

Inside the range, the limit shrinks in proportion to how far in your income falls. The formula is: reduced limit = full limit × (upper end − MAGI) ÷ (upper end − lower end). MAGI is your modified adjusted gross income — AGI with a few items added back. Then come two rules most calculators get wrong. First, the reduced limit is rounded DOWN to the nearest $10 — never up, never to the nearest. Second, if that rounded result is more than $0 but less than $200, the limit is $200. That floor is why a MAGI of $167,900 still allows $200.00 even though the raw math gives $50.00.

Step 4: Compare with what you planned

Subtract the allowed limit from what you planned. Anything above the limit is an excess contribution, taxed at 6% every year it stays in. At MAGI $160,000 single, the limit is $4,000.00, so planning the full $7,500 leaves $3,500 of excess — $210.00 a year in tax. At MAGI $168,000 the limit is $0.00, so the whole $7,500 is excess and the tax is $450.00 a year. The fix is usually to withdraw the excess, plus its earnings, before the tax-filing deadline.

The worked example

Take a single saver, age 35, MAGI $120,000, planning $7,500. Step 1: under 50, so the full limit is $7,500. Step 2: single, so the range is $153,000–$168,000. Step 3: $120,000 is below $153,000, so the allowed contribution is the full $7,500.00. Step 4: the excess is $0, so the tax is $0.00. At MAGI $160,000 the raw limit is $7,500 × 8,000 ÷ 15,000 = $4,000.00; the excess is $3,500 and the tax is $210.00 a year. At MAGI $167,900 the raw limit is $50.00, so the $200 floor lifts it to $200.00; the excess is $7,300 and the tax is $438.00 a year. At age 55 and MAGI $160,000 the raw limit is $4,586.67, which rounds down to $4,580.00; planning $8,600 leaves $4,020 of excess and $241.20 of tax a year. Rounding convention: totals are computed from unrounded values, so rounded parts may differ by a cent from their rounded sum.

Working backwards

Sometimes you want the income that goes with a limit. The highest MAGI that still gets the full $7,500 is $153,000 single — $242,000 for married filing jointly. At $153,001 the limit is already $7,490. A $5,000 limit needs a MAGI of $158,000; $2,500 needs $163,000; $1,000 needs $166,000. The $200 floor starts at $167,600, where the raw limit is exactly $200.00: at $167,599 the raw is $200.50 and rounds down to $200, and at $167,601 the raw is $199.50 and the floor holds it at $200. The limit hits $0 at $168,000 single and $252,000 for married filing jointly. At 50-plus, a $4,000 limit needs a MAGI of $161,023 (exact $161,023.26); at $161,023 the raw limit is $4,000.15, which rounds down to $4,000.00.

What changes the answer most

Your MAGI moves the answer most: $120,000 gives the full $7,500; $160,000 gives $4,000.00; $165,000 gives $1,500.00; $167,000 gives $500.00; $168,000 gives $0.00. Your filing status is next: at MAGI $247,000, married filing jointly gives $3,750.00 — half the $10,000 range gone — while at MAGI $250,000 it gives $1,500.00. Your age is third: at MAGI $100,000, age 55 gives $8,600.00 and age 35 gives $7,500.00. What you planned changes only the excess and the tax, never the limit: at MAGI $160,000, planning $5,000 leaves $1,000 of excess and $60.00 of tax, while planning $4,000 leaves nothing.

What not to do

Do not put in the full $7,500 without checking the phase-out — at MAGI $160,000 the extra $3,500 costs $210.00 a year until you take it out. Do not round the reduced limit to the nearest $10 — the IRS rounds down, and at age 55 and MAGI $160,000 that is the difference between $4,580.00 and $4,590.00. Do not assume a small limit means no limit — the $200 floor means the limit never drops below $200.00 until it hits $0. And do not leave an excess in place: the 6% tax repeats every year.

How this connects

If the phase-out wipes out your limit, the backdoor route — contributing to a traditional IRA and converting — is a different calculation with its own rules, including the pro-rata rule. To run your own numbers, use the Roth IRA contribution calculator. For the wider 2026 limits, see the 2026 retirement contribution limits, and for Roth versus traditional, see the Roth vs traditional IRA comparison.