Most guides to the American IRA stop at the same place — “for a single filer the limit phases out between $153,000 ~ $168,000.” What they do not say is how much you may actually put in when your income lands inside that band. This calculator fills that in.
1. The reduction is a straight line. Halfway through the band ($160,500) you get exactly half the limit, $3,750 — and that holds for all eight bands.
2. But two more rules attach. The figure is rounded UP to the next $10, and anything under $200 becomes $200. The short IRS page carries neither line.
3. The contribution band and the deduction band are different bands. For a single filer they sit $62,000 apart and never overlap.
Give it a filing status, an income, an age and whether a workplace plan covers you, and it walks through the Roth IRA amount → the figure before rounding → the traditional IRA deduction one line at a time.
2026, federal only. The limits and income bands are the figures in the IRS release (IR-2025-111); the round-up to $10 and the $200 floor are the rules in Publication 590-A. You have to supply the MAGI yourself — it is built by adding items back to your AGI, so this page cannot derive it. State tax, the pro-rata rule on Roth conversions and the overall 401(k) limit are not included. A separate return where only the spouse is covered could not be verified and is left out. Estimates.
What the band does to your limit
Below the band, the full amount. Above it, zero. In between it is a straight line — not a cliff at the entrance, and not a sudden collapse at the end.
Read it like this. A single filer keeps the full $7,500 up to $153,000, and from there loses $500 for every $1,000 of income (the limit $7,500 divided by the $15,000 band, or $0.50 a dollar). At the midpoint, $160,500, exactly $3,750 is left.
So the width of the band is the speed of the reduction. Filing jointly the band is only $10,000 wide, so the same rise in income costs 1.5 times as much — $750 per $1,000 ($7,500 divided by $10,000, our calculation).
The five steps the IRS gives, and the two lines the worksheet adds
The IRS page “Amount of Roth IRA contributions that you can make” sets the arithmetic out in five steps. These are its own words.
| Step | What the IRS says | Single at $160,500 |
|---|---|---|
| 1 | “Start with your modified AGI.” | $160,500 |
| 2 | “Subtract from the amount in (1)” — the bottom of the band | − $153,000 = $7,500 |
| 3 | “Divide the result in (2) by” — the width | ÷ $15,000 = 0.500 |
| 4 | “Multiply the maximum contribution limit… by the result in (3)” | $7,500 × 0.5 = $3,750 |
| 5 | “Subtract the result in (4) from the maximum contribution limit” | $7,500 − $3,750 = $3,750 |
That is the whole of that page. But the worksheet in Publication 590-A has two more lines.
- Round up to the next $10. — “If the result isn’t a multiple of $10, round it to the next highest multiple of $10. (For example, $611.40 is rounded to $620.)” Up, not to the nearest. $611.40 becomes $620.
- Anything under $200 becomes $200. — “However, if the result is less than $200, enter $200.” On the Roth side the wording is “if the result is less than $200, you may contribute $200 if you are otherwise eligible.”
With those two lines the answer changes. How much it changes has a piece of its own — the cliff the $200 floor creates. The short version: up to $199.50 inside the last $400 of the band, and under $9.50 everywhere else (our calculation).
For a single filer the two bands never meet
Saying “the IRA income band” hides something. The band where Roth IRA contributions shrink and the band where the traditional IRA deduction shrinks are not the same band.
A single filer covered by a workplace plan loses the deduction across $81,000 ~ $91,000, but the Roth contribution does not start falling until $153,000 — $62,000 higher up (our calculation). Anyone in between gets no deduction at all and can still contribute the full Roth amount.
Filing jointly the picture differs. If you are the covered spouse the deduction band is $129,000 ~ $149,000 against a Roth band of $242,000 ~ $252,000, so they are still apart — but if only your spouse is covered, your deduction band is $242,000 ~ $252,000, which is exactly the joint Roth band. Cross that point and both close at once. There is more in the traditional IRA deduction bands.
Questions this leaves
If I am inside the band, is a traditional IRA better?
This calculator does not make that judgement. It works out how much is allowed, nothing more. Which account wins depends on whether your rate now is higher or lower than your rate in retirement, and that is not settled by arithmetic. The structural difference between the two accounts is in 401(k) vs Roth IRA.
Where do I find my MAGI?
It is not a line on your return. It is built by adding items back to your adjusted gross income, and the MAGI for a Roth contribution is computed differently from the MAGI for a traditional deduction. Publication 590-A has a worksheet for each. This calculator takes the figure from you — it does not derive it.
What if my income is less than the limit?
Your income becomes the ceiling. The source says “or If less, your taxable compensation for the year.” In the worksheet this applies before the reduction — you take the lesser of the limit and your compensation first, then apply the band. That is what the “taxable compensation” field is for.
Why is the separate-return band $0 ~ $10,000?
The source attaches a condition — “married filing a separate return and you lived with your spouse at any time during the year.” If you lived together at any point in the year this is your band; if you did not live together at all, the single band applies. The condition is written into the calculator’s option.
Do the bands change at 50?
The bands stay put; only the limit rises, to $8,600 (a $1,100 catch-up). At the same income more is taken away — the band is the same width but there is more to remove — though what is left is always more than for someone under 50. One thing does move: the $200 floor starts later. For a single filer it begins $348.84 below the ceiling rather than $400.00 below it (our calculation).
What does this calculator leave out?
Everything on the 401(k) side — the $24,500 deferral limit and the $72,000 overall limit are separate rules and live in 401(k) vs Roth IRA. The pro-rata rule on Roth conversions is also out — it turns on your other IRA balances, which these inputs do not capture. State income tax is separate from the federal figures here.
Sources and where to check
IRS news release — “401(k) limit increases to $24,500 for 2026, IRA limit increases to $7,500” (IR-2025-111, based on Notice 2025-67). The $7,500 limit, the $1,100 catch-up, the three Roth income bands and the four traditional deduction bands all come from this document. (irs.gov)
IRS Publication 590-A — Contributions to Individual Retirement Arrangements (IRAs). Source for the $10 round-up and the $200 floor — “If the result isn’t a multiple of $10, round it to the next highest multiple of $10. (For example, $611.40 is rounded to $620.) However, if the result is less than $200, enter $200.” (irs.gov)
IRS — Amount of Roth IRA contributions that you can make. Source for the five steps — “Start with your modified AGI… Subtract… Divide… Multiply… Subtract the result in (4) from the maximum contribution limit before this reduction.” That page carries no rounding and no floor, and points readers to Publication 590-A for the detail. (irs.gov)
Our own calculation — the $0.50 and $0.75 per dollar, the $3,750 midpoint, the $62,000 between the two bands, the $167,600 floor threshold and the $199.50 / $9.50 gap between the two methods are worked out from the figures above. For all eight bands we walked every whole dollar of income to confirm that the result is always a multiple of $10, and is either zero or at least $200.
What we could not verify — the traditional deduction band for a separate return where only the spouse is covered. The news release does not set that combination out, so it is left out of the calculator. And the 2026 edition of the “Amount of Roth IRA contributions…” page is not up as of August 2026, so we took only the structure of the five steps from an earlier year and every figure from the news release.
As of August 2026, federal only. Not investment or tax advice — check your own position with a tax professional. The two kinds of IRA are set out in the IRA guide, the 401(k) alongside them in 401(k) vs Roth IRA, and retirement planning more broadly in retirement prep by age.
