TAXES 1905, Iowa State Income Tax Withholding
Published: February 13, 2019
Effective: Pay Period 26, 2018
Summary
The income tax withholding formula for the State of Iowa includes the following changes:
 The standard deduction amount for employees claiming zero or one withholding allowance has increased from $1,650 to $1,690.
 The standard deduction amount for employees claiming two or more withholding allowances has increased from $4,060 to $4,160.
 The tax withholding table has changed.
No action on the part of the employee or the personnel office is necessary.
Tax Formula
State Abbreviation: 
IA 
State Tax Withholding State Code: 
19 
Acceptable Exemption Form: 
IAW4 or W4 
Basis for Withholding: 
State Exemptions 
Acceptable Exemption Data: 
0/Number of Allowances 
TSP Deferred: 
Yes 
Special Coding: 
Determine the Total Number Of Allowances Claimed field as follows:

Additional Information: 
None 
Withholding Formula (Effective Pay Period 26, 2018)
 Subtract the nontaxable biweekly Thrift Savings Plan contribution from the gross biweekly wages.
 Subtract the nontaxable biweekly Federal Health Benefits Plan payment(s) (includes dental and vision insurance program and Flexible Spending Account  health care and dependent care deductions) from the amount computed in step 1.
 Add the taxable biweekly fringe benefits (i.e., taxable life insurance) to the amount computed in step 2 to obtain the adjusted gross biweekly wages.
 Multiply the adjusted gross biweekly wages by the number of pay dates in the tax year to obtain the gross annual wages.
 Multiply the biweekly Federal income tax withholding by the number of pay dates in the tax year to obtain the annual Federal income tax withholding and subtract this amount from the gross annual wages computed in step 4.
 Determine the standard deduction by applying the following guideline and subtract this amount from the result of step 5 to compute the taxable income:
If the Number of Allowances Claimed Is:
The Standard Deduction Is:
0 or 1
$1,690
2 or more
$4,160
 Apply the taxable income computed in step 6 to the following table to determine the Iowa tax withholding:
Tax Withholding Table
If the Amount of Taxable Income Is:
The Amount of Iowa Tax Withholding Should Be:
Over $0 but not over $1,333
0.33%
Over $1,333 but not over $2,666
$4.40 plus 0.67% of excess over $1,333
Over $2,666 but not over $5,331
$13.33 plus 2.25% of excess over $2,666
Over $5,331 but not over $11,995
$73.29 plus 4.14% of excess over $5,331
Over $11,995 but not over $19,992
$349.18 plus 5.63% of excess over $11,995
Over $19,992 but not over $26,656
$799.41 plus 5.96% of excess over $19,992
Over $26,656 but not over $39,984
$1,196.58 plus 6.25% of excess over $26,656
Over $39,984 but not over $59,976
$2,029.58 plus 7.44% of excess over $39,984
Over $59,976
$3,516.98 plus 8.53% of excess over $59,976
 Determine the exemption allowance by applying the following guideline and subtract this amount from the results of step 7 to compute the annual Iowa tax withholding:
Exemption Allowance = $40 x Number of Exemptions
 Divide the annual Iowa tax withholding by the number of pay dates in the tax year to obtain the biweekly Iowa tax withholding.
Resources
To view the updated tax formula, go to the
page from the dropdown menu on the National Finance Center (NFC) homepage. Select the tab and select from the menu to launch the tax map. Select the desired State from the map provided for the formula.Inquiries
For questions about NFC processing, authorized Servicing Personnel Office representatives should contact the NFC Contact Center at
or via the customer service portal.