By name: calculate description: Calculate (or recalculate) the complete Form 1040 federal tax return line by line. Uses W-2 data and intake answers from a previous /ezfile:file-taxes session. user-invocable: true
Calculate Federal Tax Return
Compute the complete Form 1040 (or 1040-SR) for a single filer with W-2 income.
Prerequisites
Before calculating, verify that return data exists:
- Check
./returns/for W-2 data (either from a prior/ezfile:file-taxessession or manually entered) - If no data exists, tell the user: "No W-2 data found. Run
/ezfile:file-taxes <path-to-w2>first."
Reference Files
Read these files before calculating:
reference/tax-year-2025.md-- brackets, standard deduction, key constantsreference/schedule-1a-2025.md-- Schedule 1-A deduction rules (if applicable)reference/credits-2025.md-- Saver's Credit and EIC rules
The 10-Step Calculation Pipeline
STEP 1: INCOME
Line 1a = Sum of W-2 Box 1 from all W-2s
Line 1z = Line 1a (only W-2 income for this profile)
Line 9 = Line 1z (total income = wages only)
STEP 2: ADJUSTMENTS TO INCOME (Schedule 1)
Only student loan interest applies for this profile:
IF student_loan_interest > 0:
raw = min(student_loan_interest, 2500)
MAGI = Line 9 (total income, before adjustments)
IF MAGI <= 85000:
deduction = raw
ELIF MAGI >= 100000:
deduction = 0
ELSE:
deduction = raw * (1 - (MAGI - 85000) / 15000)
deduction = round(deduction, 2)
Schedule_1_Line_21 = deduction
Schedule_1_Line_26 = deduction
Line_10 = deduction
ELSE:
Line_10 = 0
STEP 3: ADJUSTED GROSS INCOME
Line 11 = Line 9 - Line 10
This is the AGI -- the most important number on the return. It determines eligibility for credits and deduction phaseouts.
STEP 4: SCHEDULE 1-A DEDUCTIONS (New for 2025)
Calculate each applicable deduction with MAGI phaseout:
MAGI_for_1A = Line 11 (AGI)
# Phaseout function (shared by all Schedule 1-A deductions)
def apply_phaseout(amount, magi):
if magi <= 75000: return amount
if magi >= 100000: return 0
return round(amount * (1 - (magi - 75000) / 25000), 2)
# Tip deduction (Line 1)
tip_deduction = apply_phaseout(tip_income, MAGI_for_1A)
# Overtime deduction (Line 2)
overtime_deduction = apply_phaseout(overtime_pay, MAGI_for_1A)
# Auto loan interest (Line 3) -- max $10,000
auto_loan_deduction = apply_phaseout(min(auto_loan_interest, 10000), MAGI_for_1A)
# Senior deduction (Line 4) -- only if age 65+
IF age >= 65:
senior_1a_deduction = apply_phaseout(4000, MAGI_for_1A)
ELSE:
senior_1a_deduction = 0
Schedule_1A_Line_5 = tip_deduction + overtime_deduction + auto_loan_deduction + senior_1a_deduction
Line_12c = Schedule_1A_Line_5
STEP 5: STANDARD DEDUCTION
IF age >= 65:
Line_12a = 17750 (single, 65+: $15,750 + $2,000 additional)
ELSE:
Line_12a = 15750 (single, under 65)
STEP 6: TOTAL DEDUCTIONS
Line_12b = 0 (no charitable deduction for this profile)
Line_13 = 0 (no QBI deduction for W-2 filers)
Line_14 = Line_12a + Line_12b + Line_12c + Line_13
STEP 7: TAXABLE INCOME
Line_15 = max(Line_11 - Line_14, 0)
STEP 8: TAX FROM BRACKETS
Apply 2025 single filer brackets:
taxable = Line_15
if taxable <= 11925:
tax = taxable * 0.10
elif taxable <= 48475:
tax = 1192.50 + (taxable - 11925) * 0.12
elif taxable <= 103350:
tax = 5578.50 + (taxable - 48475) * 0.22
elif taxable <= 197300:
tax = 17651.00 + (taxable - 103350) * 0.24
elif taxable <= 250525:
tax = 40099.00 + (taxable - 197300) * 0.32
elif taxable <= 626350:
tax = 57131.00 + (taxable - 250525) * 0.35
else:
tax = 188769.75 + (taxable - 626350) * 0.37
Line_16 = round(tax, 2)
STEP 9: CREDITS
Saver's Credit (Form 8880) -- Nonrefundable:
retirement_contributions = sum of W-2 Box 12 amounts for codes D, E, G, AA, BB
eligible_amount = min(retirement_contributions, 2000)
IF eligible_amount > 0:
IF Line_11 <= 23750:
credit_rate = 0.50
ELIF Line_11 <= 25750:
credit_rate = 0.20
ELIF Line_11 <= 39500:
credit_rate = 0.10
ELSE:
credit_rate = 0
savers_credit = round(eligible_amount * credit_rate, 2)
savers_credit = min(savers_credit, Line_16) # Can't exceed tax
ELSE:
savers_credit = 0
Line_19 = savers_credit
Earned Income Credit -- Refundable:
IF Line_11 < 19104 AND age >= 25 AND age <= 64:
# Simplified EIC calculation (no qualifying children)
earned_income = Line_1a
IF earned_income <= 8490:
eic = round(earned_income * 0.0765, 2)
ELIF earned_income <= 10330:
eic = 649 # Maximum
ELSE:
eic = max(round(649 - (earned_income - 10330) * 0.0765, 2), 0)
# Also check against AGI
IF Line_11 > 10330:
agi_eic = max(round(649 - (Line_11 - 10330) * 0.0765, 2), 0)
eic = min(eic, agi_eic)
Line_27 = eic
ELSE:
Line_27 = 0
Total Tax:
Line_22 = max(Line_16 - Line_19, 0)
Line_24 = Line_22 (no additional taxes for this profile)
STEP 10: PAYMENTS & RESULT
Line_25a = Sum of W-2 Box 2 from all W-2s
Line_25d = Line_25a
Line_33 = Line_25d + Line_27 (withholding + refundable credits)
IF Line_33 > Line_24:
Line_34 = Line_33 - Line_24 → REFUND
Line_37 = 0
ELSE:
Line_34 = 0
Line_37 = Line_24 - Line_33 → AMOUNT OWED
Verification
After computing, verify these invariants:
- Line 11 = Line 9 - Line 10
- Line 15 = max(Line 11 - Line 14, 0)
- Line 15 >= 0
- Line 16 >= 0
- Line 22 = max(Line 16 - Line 19, 0)
- Line 24 = Line 22
- Line 33 = Line 25d + Line 27
- Line 34 = max(Line 33 - Line 24, 0) OR Line 37 = max(Line 24 - Line 33, 0)
- Line 34 and Line 37 cannot both be > 0
If any invariant fails, display the error and recompute.
Output
Save to Files
Write complete return to ./returns/return-2025.json:
{
"tax_year": 2025,
"filing_status": "single",
"form": "1040",
"line_1a": 0,
"line_9": 0,
"line_10": 0,
"line_11": 0,
"line_12a": 0,
"line_12c": 0,
"line_14": 0,
"line_15": 0,
"line_16": 0,
"line_19": 0,
"line_22": 0,
"line_24": 0,
"line_25a": 0,
"line_27": 0,
"line_33": 0,
"line_34": 0,
"line_37": 0,
"schedules": {
"schedule_1": { "line_21": 0, "line_26": 0 },
"schedule_1a": { "line_1": 0, "line_2": 0, "line_3": 0, "line_4": 0, "line_5": 0 }
}
}
Display Summary
Show the full return summary using the format from the review skill.
Suggest Next Steps
- Run
/ezfile:checklistfor filing instructions - Run
/ezfile:explain <topic>for explanations - Run
/ezfile:reviewto see the summary again