Idaho State Tax Commission

Idaho State Tax Commission

Avoid a Tax Surprise – Act Now!

Recent tax laws have changed the amount of income taxes withheld from your paycheck.

If you don't withhold enough tax, you could have an unexpected tax bill when you file your 2018 income tax return.

Review your federal form W-4, Employee's Allowance Certificate, now to see if you have the right amount of federal and state income taxes withheld from your paycheck.

Steps to take:

  1. Use the withholding calculator at to estimate your federal withholding.
  2. Use the 2018 W-4 Worksheet for Idaho to estimate your Idaho withholding.
  3. Make any needed changes to Form W-4 and give it to your employer.


For individuals
For employers

Estimate how much tax you'll owe

  1. Add together the income from all your W-2s, 1099s, etc.
  2. Subtract your standard deduction from #1 (depends on your filing status)
    1. Single = $12,000
    2. Head of Household = $18,000
    3. Married = $24,000
  3. The result is your taxable income
  4. Find your taxable income for your return filing status in the 2018 individual income tax tables and determine your tax

Law changes that affect 2018 tax returns

  • Increased standard deductions:
    • Single = $12,000
    • Head of Household = $18,000
    • Married Filing Jointly = $24,000
  • Eliminated personal exemptions.
  • Eliminated dependent exemptions.
  • Eliminated/capped most itemized deductions.
  • Idaho has a new nonrefundable Idaho child tax credit of $205 for each qualifying child.
  • Idaho individual income tax rates have been reduced by 0.475%. The top rate for individuals is now 6.925%.
  • More information about recent tax law changes

Guidance for retirement and other sources of nonwage income

If you're receiving retirement or other sources of nonwage income:

  1. Determine if the income is taxable in Idaho.
    • See the Idaho Income Tax Instructions for guidance
    • Taxable income can be:
      • Retirement income
      • Interest
      • Dividends
    • Generally, Idaho doesn't tax Social Security income.
  2. If the income is taxable, follow the next steps.

Note: The entity paying the nonwage income might not withhold Idaho tax. It's your responsibility to estimate the tax you'll owe and be prepared to pay it.

If the entity paying the nonwage income will withhold Idaho tax for you:

  1. Use the 2018 W-4 Worksheet for Idaho to determine:
    • Your W-4 box 3 filing status
    • Your Idaho allowance
    • Any additional amount to withhold
      • See lines 12-20 of Part C
      • Consider each source of taxable income as a "job"
  2. Use the information from the worksheet to complete a W-4, or use the entity's W-4 substitute

If the entity paying the nonwage income won't withhold Idaho tax for you:

  1. Estimate your income tax for the nonwage income source:
    1. Estimate your annual income for the source
    2. Estimate your tax on the income. Use the 2018 income tax rate table for your return filing status, and find the total tax you'll owe.
  2. Pay the tax you owe.
    • Make estimated payments directly to the Tax Commission
      • Use Form 51, Estimated Payment of Idaho Individual Income Tax (mark the 2018 box), or
      • Use Quick Pay, online (no log-in needed).
    • Pay the tax on or before April 15


Presentation on W-4 Worksheet (including Q&A following)

Webinar on W-4 Worksheet in partnership with the Idaho Society of Certified Public Accountants (ISCPA)

Page last updated July 27, 2018. Last full review of page: June 21, 2018.

This information is for general guidance only. Tax laws are complex and change regularly. We can't cover every circumstance in our guides. This guidance may not apply to your situation. Please contact us with any questions. We work to provide current and accurate information. But some information could have technical inaccuracies or typographical errors. If there's a conflict between current tax law and this information, current tax law will govern.