Federal Tax Code Assumptions
Tax Base All income from whatever source derived
Standard deduction $12,000 single/$24,000 married filing jointly
Taxpayer can claim deductions per IRS Form 1040 and related schedules
Additionally, filers can claim a child tax credit of $3,000 per dependent child. This tax credit phases out 15 cents for every dollar of AGI above $150K single and $250K married filing jointly.
Federal tax brackets - For this question, assume these tax rates apply to taxable income from all income sources (no special rate for capital gains)
Tax Rate Single Filer Married Filing Jointly
10% $0-$10K $0-$20K
12% $10K+ $40K $20K+-$80K
22% $40K+-$85K $80K+-$170K
24% $85K+-$160K $170K+-$320K
32% $160K+$205K $320K+ $410K
35% $205K+-$510K $410K+ $610K
37% $510K+ $610K+
State Tax Code Assumptions
Tax base federal AGI
State income tax rate - 4.55%
Filers can claim a tax credit equal to the sum of 6% of itemized or standard deduction claimed plus $2,000 per dependent child. This tax credit phases out 1.3 cents for each dollar of AGI above $17,000 single and $34,000 married filing jointly.
Taxpayer Assumptions
Lucia and Antoine are a married couple filing jointly and have two qualifying dependent children. Together they have $120,000 of wage income, $2,000 of interest income, and $5,000 in realized long-term capital gains. They have a combined $5,000 of qualifying "above-the-line" health savings account contributions, IRA contributions, and student loan interest; $8,000 of qualifying charitable contributions; $10,000 of qualifying mortgage interest, and $10,000 of qualifying state and local taxes.
(1) What is federal adjusted gross income (AGI)?
(2) What is federal taxable income?
(3) What is federal tax before any tax credits?
(4) What is federal tax after any tax credits?
(5) What is the federal average tax rate with respect to AGI?
(6) What is the federal statutory marginal tax rate?
(7) What is the federal effective marginal tax rate with respect to AGI?
(8) What is the state tax after any applicable tax credits?
(9) What is the state average tax rate with respect to AGI?
(10) What is the state statutory marginal tax rate?
(11) What is the state effective marginal tax rate with respect to AGI?
(12) If the taxpayers made a total $2,000 qualifying retirement contribution, how much of this $2,000 would be offset by reduced tax?