Tax · super (composes 2 primitives)
Marriage tax penalty / bonus
Type both incomes. We compute the federal tax as two singles vs MFJ, surface bracket compression at high incomes, compare standard deductions, identify SALT-cap and IRA-deduction phase-outs, and report the annual marriage penalty (or bonus) in dollars.
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Inputs
Result
Marriage PENALTY: $3,060/yr — MFJ pays $3,060 more than filing as two singles.
Roughly neutral: Delta inside ±$5,000. Not a deciding factor either way; SALT cap and IRA phase-out can swing it more than brackets at this income level.
- 1
Total federal tax — two singles
$56,914
Partner A: $28,067 on $146,750 taxable · B: $28,847 on $150,000
- 2
Federal tax — MFJ
$59,974
$309,500 taxable income, $30,500 deduction
- 3
Annual delta
$3,060
Cost of being married, federal-tax-only
- 4
Bracket compression
Not applicable
Brackets are 2× single brackets up to ~$394k taxable, so no compression at lower income levels
- 5
SALT cap penalty
$3,200
MFJ cap is the same $10k as a single — losing $10,000 of deduction
- 6
Traditional IRA deduction phase-out
Phased out
Combined AGI of $340,000 exceeds the $143k MFJ phase-out for covered spouses
- 7
Standard deduction comparison
$43,250 singles vs $30,500 MFJ
Singles get more total deduction
Assumptions & notes
- Federal brackets are 2026 estimates. Singles: 22% kicks in at $48,475, 32% at $197,300. MFJ: 22% at $96,950, 32% at $394,600.
- SALT cap of $10,000 is the same for singles and MFJ — that's the biggest source of compression for high-tax states (CA, NY, NJ).
- Marriage bonus typically ~2%-5% of household income when one spouse earns ≥75% of total. Penalty when both earn similarly at high incomes.
Multi-scenario comparison
What if — ±20% on one input
| Scenario | Partner A annual income | Headline | Δ vs baseline | Magnitude |
|---|---|---|---|---|
| −20% (cautious) | $140,000 | Marriage PENALTY: $3,060/yr — MFJ pays $3,060 more than filing as two singles. | $-8,400 | |
| Baseline | $175,000 | Marriage PENALTY: $3,060/yr — MFJ pays $3,060 more than filing as two singles. | 0 | |
| +20% (aggressive) | $210,000 | Marriage PENALTY: $3,060/yr — MFJ pays $3,060 more than filing as two singles. | +$8,400 |
Try the input with the highest sensitivity (above). The Δ column shows the dollar swing from a 20% move — that's how much room you have for a counter, raise, or hedge.
Goal seek
Solve for an input value
Pick the input you want to vary and the output you care about. We'll find the input value that gets you to the target. Bisection-based; converges in < 50 iterations.
Monte Carlo simulation
Distribution under input uncertainty (500 trials)
We perturb every numeric input with normal-distributed noise (10–25% sigma depending on input type) and run 500 compute trials. The output is a probability distribution, not a single number — closer to how finance actually works.
Most-leveraged inputs (sensitivity analysis)
Where to focus — what moves the answer most
Each input perturbed ±10%; measured impact on Total federal tax — two singles. Higher elasticity = bigger lever.
- 1
Partner A annual income
Elasticity ↑ 0.74× — 10% change in this input increases Total federal tax — two singles by 7.4%.
- 2
Partner B annual income
Elasticity ↑ 0.70× — 10% change in this input increases Total federal tax — two singles by 7.0%.
- 3
Combined mortgage interest
Elasticity ↓ 0.07× — 10% change in this input decreases Total federal tax — two singles by 0.7%.
- 4
Combined charitable
Elasticity ↓ 0.01× — 10% change in this input decreases Total federal tax — two singles by 0.1%.
ShowMath is the only calc site that surfaces this. Adjust the highest-leverage input first — that's where small moves create big results.
Chain payload (for the 3D constellation)
{
"slug": "marriage-tax-penalty",
"depth": 1,
"primitives": [
"tax-bracket-calculator",
"filing-status-calculator"
],
"composes": [],
"chain": [
{
"key": "two_singles",
"label": "Total federal tax — two singles",
"primitive": "tax-bracket-calculator",
"numeric": 56914
},
{
"key": "mfj",
"label": "Federal tax — MFJ",
"primitive": "filing-status-calculator",
"numeric": 59974
},
{
"key": "delta",
"label": "Annual delta",
"numeric": 3060
},
{
"key": "bracket_compression",
"label": "Bracket compression",
"numeric": 0
},
{
"key": "salt_cap",
"label": "SALT cap penalty",
"numeric": 3200
},
{
"key": "ira_phaseout",
"label": "Traditional IRA deduction phase-out",
"numeric": 1
},
{
"key": "deduction_compare",
"label": "Standard deduction comparison",
"numeric": 30500
}
]
}The chain explained
Each step above corresponds to a primitive calculator. Click any to see the stand-alone version with its own explainer + sources.
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- filing status calculatorshipping soon
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