The method
- Find the deductible amount from your inputs: the overtime premium, qualified tips, the senior amount or car loan interest.
- Apply the yearly cap and the income phase-out exactly as Schedule 1-A does.
- Figure taxable income before the deduction: your total income minus the standard deduction for your filing status, plus the extra standard deduction for age 65 or older on the senior calculator.
- Compute federal income tax on that amount and on the amount after the deduction, bracket by bracket, and show the difference as the tax you keep.
Caps and phase-outs
| Deduction | Cap | Phase-out |
|---|---|---|
| Overtime | $12,500 ($25,000 joint) | −$100 per full $1,000 of MAGI over $150,000 ($300,000 joint) |
| Tips | $25,000 per return | −$100 per full $1,000 over $150,000 ($300,000 joint) |
| Senior | $6,000 per person 65+ | −6% of MAGI over $75,000 ($150,000 joint), per person |
| Car loan interest | $10,000 | −$200 per $1,000 or part of $1,000 over $100,000 ($200,000 joint) |
Rounding follows the 2025 Schedule 1-A: the tips and overtime phase-outs round down to whole thousands, the car loan phase-out rounds up.
Tax figures used
2025 brackets and standard deductions from IRS Rev. Proc. 2024-40 as amended by the 2025 law; 2026 figures from Rev. Proc. 2025-32. Standard deduction: $15,750 single, $31,500 joint, $23,625 head of household for 2025; $16,100, $32,200 and $24,150 for 2026. Extra standard deduction at 65 or older: $2,000 unmarried and $1,600 married for 2025; $2,050 and $1,650 for 2026.
What the estimate leaves out
- Tax credits, other deductions, itemizing, and the alternative minimum tax.
- Social Security and Medicare tax, which the deductions don't change.
- State and local income tax.
- The difference between total income and modified adjusted gross income; for most people they're close.
Your data
The calculators run in your browser. The numbers you type aren't sent to us or stored. The one exception is the VIN check, which sends the VIN you enter to the National Highway Traffic Safety Administration's public decoder to look up the assembly plant.