(no form number): Itemized Deduction Worksheet for Idaho (Revision)
Idaho · Idaho Tax Commission · Used for tax years 2024, 2025, 2026
The Itemized Deduction Worksheet for Idaho calculates an additional number to add to the allowances claimed on Form ID W-4, Employee’s Withholding Allowance Certificate. The provided worksheet uses estimated itemized deductions and standard deduction amounts for tax year 2025.
Who files this form
Complete lines 1–4 if you plan to itemize deductions. If you’re married and both spouses work, or either spouse has multiple jobs, complete this worksheet for the highest-paying job.
The worksheet’s deduction amounts and estimates are specifically for Tax Year 2025.
What you'll need
To complete the worksheet, have these figures available:
- Your estimated Tax Year 2025 itemized deductions: qualifying mortgage interest, charitable contributions, real estate taxes, and medical expenses greater than 7.5% of your income.
- Your filing status, which determines your Tax Year 2025 standard deduction.
- The number of Idaho allowances you’re claiming on line 1 of Form ID W-4, Employee’s Withholding Allowance Certificate.
Common mistakes
- Don’t include state and local income taxes or general sales taxes in your itemized deduction estimate.
- If you’re married and both spouses work, or either spouse has multiple jobs, use the highest-paying job for this worksheet.
- If line 1 minus line 2 is less than zero, enter 0 on line 3.
- After dividing line 3 by $3,868, round down as directed on line 4.
- Add the line 4 result to the Idaho allowances you’re claiming on line 1 of Form ID W-4.
Questions people ask
Which itemized deductions go on line 1?
Enter your estimated Tax Year 2025 qualifying mortgage interest, charitable contributions, real estate taxes, and medical expenses greater than 7.5% of your income. Don’t include state and local income taxes or general sales taxes. The worksheet refers to IRS Publication 505.
What standard deduction should I enter on line 2?
For Tax Year 2025, enter:
- $15,000 if single or married filing separately.
- $22,500 if head of household.
- $30,000 if married filing jointly or a qualifying surviving spouse with qualifying dependents.
How do I calculate lines 3 and 4?
Subtract line 2 from line 1. Enter the result on line 3, or enter 0 if the result is negative. Divide line 3 by $3,868 and enter the result on line 4. The worksheet directs you to round down to the nearest whole dollar.
What do I do with the result on line 4?
Add it to the number of Idaho allowances you’re claiming on line 1 of Form ID W-4, Employee’s Withholding Allowance Certificate.