Quick Answer
Quick Answer: Your eligible IRA contribution starts from the 2026 base limit of $7,500, plus a $1,100 catch-up if you are age 50 or older (a $8,600 full cap). For a Roth IRA the engine then reduces that cap on a straight line across your filing status's income phase-out band. For a single filer, age 45, with $160,500 of MAGI contributing to a Roth, the engine returns an eligible contribution of $3,750 -- exactly half the cap, because that income sits halfway through the $153,000-to-$168,000 phase-out range. This page shows the complete math behind every number our calculator produces.
Key Takeaways
- The engine uses four inputs -- age, filing status, MAGI (modified adjusted gross income), and IRA type (Traditional or Roth)
- The 2026 base limit is $7,500; age 50+ adds a $1,100 catch-up for an $8,600 full cap
- A Roth contribution phases out with income; a Traditional contribution never does -- only its deductibility does
- In the phase-out band the engine reduces the cap in proportion to how far your MAGI is into the range, rounded to the nearest $10 with a $200 floor
- The limit is the combined total across all your IRAs, and it is capped by your earned income for the year
IRA Contribution Limits in Plain English
An IRA contribution limit is not a single number -- it is a cap that steps down for two reasons. First, everyone starts from the same annual base amount, and people age 50 and older get an extra "catch-up" slice on top. Second, for a Roth IRA, higher earners lose access gradually: as your income climbs through a set band, your allowed contribution slides from the full cap down to zero.
The calculator walks the same three steps every time:
- Start with the base limit for the year ($7,500 in 2026).
- Add the catch-up if you are 50 or older ($1,100), giving a full cap of $8,600.
- For a Roth, shrink that cap in proportion to how far your income sits inside the phase-out band; for a Traditional IRA, keep the full cap and instead report whether the contribution is tax-deductible.
One critical distinction the engine encodes: a Traditional IRA contribution is never blocked by income -- anyone with earned income can contribute the full cap. What income can take away is the tax deduction, and only when you are covered by a workplace retirement plan. A Roth contribution, by contrast, is directly phased out by income. The IRS IRA contribution-limit page(opens in new tab) is the authoritative reference for these rules.
The Formula
Here are the exact rules used by our IRA Calculator. The engine first builds the full cap, then applies the Roth phase-out if it applies:
fullCap = base + (age ≥ 50 ? catchUp : 0)
For a Roth IRA, the eligible contribution depends on where MAGI falls relative to the phase-out band [start, end]:
if MAGI ≤ start → eligible = fullCap
if MAGI ≥ end → eligible = 0
otherwise: ratio = (MAGI − start) ÷ (end − start)
eligible = round$10( fullCap × (1 − ratio) ), floor $200
For a Traditional IRA the contribution is simply eligible = fullCap (never income-phased), and the engine separately reports a deduction status of fully / partially / not deductible based on the §219(g) band. Two rules the engine applies exactly:
- $10 rounding, $200 floor: a partial Roth amount is rounded to the nearest $10, but never below $200 while any contribution is still allowed (IRC §408A(c)(3)(B)).
- Earned-income cap: you cannot contribute more than your taxable compensation for the year -- a ceiling that sits on top of every number here.
Variable Definitions
| Variable | Meaning | Units / How to Enter | Example (single, 45, $160,500, Roth) |
|---|---|---|---|
| base | 2026 base contribution limit | USD (fixed by the IRS for the year) | $7,500 |
| catchUp | Age 50+ catch-up amount | USD, added only if age ≥ 50 | $0 (age 45) |
| fullCap | base + catchUp | USD | $7,500 |
| MAGI | Modified adjusted gross income | USD per year | $160,500 |
| start, end | Roth phase-out band for your filing status | USD (2026 IRS thresholds) | $153,000 – $168,000 |
| ratio | Fraction of the band your MAGI has crossed | (MAGI − start) ÷ (end − start) | 7,500 ÷ 15,000 = 0.50 |
Valid Input Ranges
Our calculation engine accepts an age from 18 to 100, a MAGI from $0 to $10,000,000, one of four filing statuses (single, married filing jointly, married filing separately, head of household), and an IRA type of Traditional or Roth. These bounds match the engine exactly.
Worked Example: Single Filer, Age 45, $160,500 MAGI, Roth
This section walks through every step for a Roth contribution that lands squarely inside the phase-out band. You can follow along with a standard calculator and verify the result against our IRA Calculator.
Step 1: Build the Full Cap
- Base = $7,500 (2026)
- Age 45 is under 50, so catch-up = $0
- fullCap = $7,500 + $0 = $7,500
Step 2: Locate MAGI in the Phase-Out Band
Single filers phase out between $153,000 and $168,000 for 2026.
- MAGI $160,500 is above $153,000 and below $168,000, so a partial contribution applies
- Band width = $168,000 − $153,000 = $15,000
Step 3: Compute the Reduction Ratio
- Amount into the band = $160,500 − $153,000 = $7,500
- ratio = $7,500 ÷ $15,000 = 0.50
Step 4: Apply the Ratio and Round
- reduced = $7,500 × (1 − 0.50) = $3,750
- Round to the nearest $10: $3,750 is already a multiple of $10
- eligibleContribution = $3,750
Step 5: Read the Result
- Eligible Roth contribution = $3,750
- Phase-out reduction = $7,500 − $3,750 = $3,750
Read together: this saver can put $3,750 into a Roth IRA for 2026 -- half the full cap, because their income sits halfway through the phase-out band. Every figure above was produced by the calculator's engine with inputs age = 45, filing status = single, MAGI = $160,500, type = Roth (verified July 5, 2026).
How Income Changes the Roth Limit
Because the Roth reduction is a straight line, every $3,000 of MAGI inside the band lops another $1,500 off the cap. The table below holds the filer fixed (single, age 45, $7,500 full cap, Roth) and varies only MAGI. Every row was computed by the engine.
| MAGI | Eligible Roth Contribution | Phase-Out Reduction |
|---|---|---|
| $150,000 (below band) | $7,500 | $0 |
| $153,000 (band start) | $7,500 | $0 |
| $156,000 | $6,000 | $1,500 |
| $159,000 | $4,500 | $3,000 |
| $160,500 (worked example) | $3,750 | $3,750 |
| $162,000 | $3,000 | $4,500 |
| $165,000 | $1,500 | $6,000 |
| $168,000 (band end) | $0 | $7,500 |
The cliff is smooth, not sudden: a dollar more of income never wipes out the whole contribution at once, but by the top of the band ($168,000) the Roth door is fully closed. Savers just over the line often use a backdoor or mega-backdoor Roth instead.
Age 50+ Shifts Every Row Up
Add the $1,100 catch-up and the full cap becomes $8,600, so the same single filer's engine-computed Roth amounts rise to $8,600 at $150,000 MAGI, $6,880 at $156,000, $3,440 at $162,000, and $0 at $168,000. The phase-out band is identical; only the starting cap is larger.
Filing Status, Catch-Up, and the Traditional Deduction
Two levers sit outside the worked example: which filing-status band applies, and -- for Traditional IRAs -- whether the contribution is tax-deductible. Both are encoded in the engine.
2026 Roth Phase-Out Bands
| Filing Status | Phase-Out Start | Phase-Out End |
|---|---|---|
| Single / Head of Household | $153,000 | $168,000 |
| Married Filing Jointly | $242,000 | $252,000 |
| Married Filing Separately | $0 | $10,000 |
The same straight-line math applies with the joint band: an engine run for a married-filing-jointly Roth (age 45) returns the full $7,500 at $242,000 MAGI, $3,750 at $247,000 (the band midpoint), and $0 at $252,000.
Traditional IRA: Deduction, Not Contribution
For a Traditional IRA the engine always returns the full contribution cap, then reports a deduction status. For a single filer covered by a workplace plan in 2026, the deduction phases out between $81,000 and $91,000: the engine reports fullyDeductible at $70,000 MAGI, partiallyDeductible at $85,000, and notDeductible at $95,000 -- while the contribution stays $7,500 in all three cases. If neither you nor your spouse is covered by a workplace plan, the Traditional deduction is not phased out at all.
Data Sources and Methodology Notes
Our IRA Calculator applies the 2026 limits and phase-out bands documented above. The engine carries full precision through the reduction ratio and rounds only the final eligible amount to the IRS $10 increment.
Calculation Engine
The same contribution-limit logic runs in the browser and in our public calculator API / MCP server (tool: ira_contribution_limit — full input/output schema in the API reference), so a result is identical wherever you access it. The engine returns the eligible contribution, the full cap, the catch-up amount, the phase-out reduction, and the Traditional deduction status. As a reproducibility check, the worked example and every table figure on this page were generated by that engine (verified July 5, 2026).
Reference Data
- 2026 limits ($7,500 base, $1,100 catch-up) and phase-out bands are set by IRS Notice 2025-67 and related IRS guidance(opens in new tab).
- The Roth phase-out and $10-rounding / $200-floor rule follow IRC §408A(c)(3) as explained on IRS.gov(opens in new tab).
Assumptions and Limitations
- This tool computes the contribution limit only -- it does not project future account balances. For growth math, see our compound interest methodology.
- The result assumes your earned income is at least the eligible amount; you cannot contribute more than your taxable compensation for the year.
- The Traditional deduction phase-out shown applies to taxpayers covered by a workplace retirement plan; different thresholds apply when only a spouse is covered.
- Figures are 2026 values. Limits are re-indexed annually, so verify the current year before relying on any number.
Frequently Asked Questions
The calculator starts from the 2026 base limit of $7,500, adds a $1,100 catch-up if you are age 50 or older (an $8,600 full cap), and then, for a Roth IRA, reduces that cap on a straight line across your filing status's MAGI phase-out range. For a single filer age 45 with $160,500 of MAGI contributing to a Roth, the engine returns an eligible contribution of $3,750 -- exactly half the $7,500 cap, because $160,500 sits halfway through the $153,000-to-$168,000 band.
For 2026 the base IRA contribution limit is $7,500 (per IRS Notice 2025-67). If you are age 50 or older, a $1,100 catch-up raises the full cap to $8,600. This limit is the combined total across all of your Traditional and Roth IRAs, not a per-account amount.
Above a MAGI threshold your Roth contribution shrinks on a straight line to zero. For 2026 the single and head-of-household band is $153,000 to $168,000, and the married-filing-jointly band is $242,000 to $252,000. The engine computes the reduction ratio = (MAGI − start) ÷ (end − start), multiplies the full cap by (1 − ratio), and rounds to the nearest $10 with a $200 floor if any contribution is still allowed. At or above the top of the band the Roth contribution is $0.
The Traditional IRA contribution itself is never income-limited -- anyone with earned income can contribute up to $7,500 ($8,600 if 50+). What phases out with income is the tax deduction, and only if you (or your spouse) are covered by a workplace retirement plan. For a covered single filer in 2026 the deduction phases out between $81,000 and $91,000. The engine reports this as a separate fullyDeductible / partiallyDeductible / notDeductible status alongside the contribution amount.
The methodology on this page covers the contribution-limit engine -- how much you are eligible to put in. That is the regulatory core that our IRA calculator and the ira_contribution_limit MCP tool both run. Any long-term balance projection is a separate, assumption-driven feature; for compound-growth math see our compound interest calculator methodology.
Sources
Important Disclaimer
Disclaimer: This content is for educational and informational purposes only and does not constitute financial, tax, or legal advice. Individual circumstances vary, and you should consult with a qualified tax or financial professional before making contribution decisions. Contribution limits, phase-out bands, and deduction rules are set by the IRS and change from year to year; the figures here are 2026 values. While we strive for accuracy, laws and regulations change over time. Data current as of July 2026.
Content reviewed by the Digital Calculator Team. Learn more about our accuracy standards.