Illinois financial affidavit: working out monthly amounts

Published October 28, 2026

Every amount on Illinois's Financial Affidavit (Family & Divorce Cases) is monthly: section 5 is "My Monthly Gross Income From All Sources" and section 9 is "My Monthly Living Expenses". Few people are paid, or pay their bills, once a month. The instruction sheet that comes with the form, ATJ 250.3, explains how to convert, and this guide sets that out with worked examples. It is general information, not legal advice.

Pay that is not monthly

If you are not paid monthly, you will need to convert your income into monthly amounts. For example, if you are paid $600 per week, multiply $600 by 52 weeks to get your pay per year and then divide that amount by 12 months to get your monthly pay ($600 x 52 = $31,200 ÷ 12 = $2,600 per month).

The instructions then give a table for each schedule. With examples:

Section 5 asks for gross income, before taxes and deductions, so the amount to convert is the gross on your pay stub, not the deposit in your bank account. Taxes and other payroll deductions go in section 6. Multiplying a weekly amount by 4 instead of 52 ÷ 12 leaves out about a month of pay a year: $650 x 4 = $2,600, against $2,816.67.

Expenses that vary or come once or twice a year

Some expenses vary during the year or are paid only once or twice a year. In those cases, calculate the total yearly amount you pay and then divide by 12 to reach the average monthly amount.

The instructions' example is car insurance of $600 twice a year: $1,200 a year ÷ 12 = $100 a month. The same works for property tax paid in two installments, a yearly city sticker, or a summer camp paid in one go. In section 9b the line is "Insurance, license, registration and city sticker", so all three can be added before dividing.

Monthly averages from bank and card statements

For spending that changes every month, such as groceries, gas or eating out, the same idea applies to your statements: add up what was spent on each line over a period and divide by the number of months. Twelve months covers the seasons (heating in winter, camps in summer). A worked example for groceries:

1. Add every grocery, household supplies and toiletries purchase across your checking account and every card for the 12 months: say $8,425.80.
2. Divide by 12: $702.15 a month for 9a "Groceries, household supplies, and toiletries".
3. Do the same for each line, keeping the purchases behind each total so you can show where it came from.

Two things inflate totals built from statements. A payment from checking to your credit card is not an expense: the card's purchases already are (see credit card payments versus purchases). And money moved between your own accounts is not income or spending (see transfers between your own accounts). The instructions also say: "Do not list the same income, expense, asset, or debt in more than one section of the Financial Affidavit."

Lines that share money

The first line of section 5 is "Regular employment/self-employment earnings from all jobs (salary, wages, base pay, etc.)", so wages and self-employment earnings meet on one line. For wages the figure is the gross from your stubs; for self-employment it is your earnings from the business. Section 3c asks separately for the business's gross receipts and ordinary and necessary expenses, last year and so far this year. Section 9a puts "Groceries, household supplies, and toiletries" on one line, and section 9c puts "Entertainment, dining out, and hobbies" on one line, so store runs and restaurant meals land in different groups.

Financial Affidavit Numbers adds up and averages your statements' transactions on each line of the Illinois form over the months you choose, uses the instructions' conversions for gross pay you type from a pay stub, and lists every transaction behind each figure. It does not fill in the affidavit; you copy the figures you decide to use.

Common questions

How do I convert biweekly pay to monthly for an Illinois financial affidavit?

Illinois's instructions say: amount every two weeks x 26 ÷ 12. For $1,400 every two weeks that is $36,400 a year, or $3,033.33 a month.

How do I convert weekly pay to monthly in Illinois?

Multiply by 52 and divide by 12. The instructions' own example: $600 x 52 = $31,200 ÷ 12 = $2,600 per month.

How do I list an expense paid twice a year?

Add up the yearly total and divide by 12. The instructions' example is car insurance of $600 twice a year: $1,200 ÷ 12 = $100 a month.

Is income on the Illinois financial affidavit gross or net?

Section 5 is gross monthly income, before taxes and deductions. Payroll deductions such as federal and state tax, FICA and Medicare go in section 6.

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