Most Broward County Child Support attorneys, as well as mediators and Judges at the courthouse, use family law financial software to calculate child support, and there are some child support calculators on-line. If you're attempting to determine child support though for yourself, it's going to be a good idea for you to make the calculations by hand, using Florida's Child Support Guidelines Worksheet - to be sure you get the figures right, including any adjustment for the number of "overnights" each parent spends with the child(ren) (more below on this), and to be sure you'll understand the issues and items that go into determining child support under Florida law.
The first step is to determine each parent's net-income. The income and deductions that are considered in determining net income for child support are set forth in detail in Florida's child support statute, but the easiest way to arrive at the amount is to complete the Florida Family Law Financial Affidavit. There is a separate form if you make under $50,000 per year gross income and one for over $50,000. The financial affidavits, child support worksheet as well as other family law forms can be found at Florida Family Law Forms. As you can see on the child support worksheet, you need each parent's net income to calculate child support. If you know the other parent's monthly gross income and their monthly health insurance costs, figuring their net income may not be difficult for you. There are paycheck calculators on-line that will assist you in determining monthly income tax, and social security and medicare taxes. The amounts you list for monthly taxes on the financial affidavit will not necessarily be the amounts deducted each month from a paycheck - some people, based on the number of exemptions they list on their W-4, have more or less than the actual amount of the taxes they'll owe at the end of the year deducted from their paycheck. In cases where you don't know the other parent's income, there is a part of litigation called "discovery" through which you are entitled to receive financial information and records from the other parent, including their financial affidavit and copies of bank account and other statements. If you believe the other party is hiding income, there are more extensive discovery methods available, and some litigated cases will involve using a "forensic accountant" as an expert witness in establishing the other party's income.
Once you have the net income for each parent, you can proceed with filling out the blanks in the Child Support Guidelines Worksheet. The Worksheet tells you step-by-step what amounts to add or subtract from what, and the other parts of the calculations. The concept is basically that you add together the parents' net incomes to arrive at an amount for combined net income, then use the child support chart included in the instructions for the Worksheet to come up with the "Basic Monthly Obligation". If you look on the child support chart, you'll see income amounts on the left side, and the number of children across the top, and the Basic Monthly Obligation for your situation, as shown on the chart, is the amount the Florida Legislature has determined is the amount that should be used as the basic child support amount (before health and daycare costs) for parents with a certain combined net income and number of children. The Worksheet will then take you through determining your share of the basic monthly obligation, which is based on your percentage share of the parents' combined net-income. For example if the parents' combined net income is $3,000/month and your monthly net-income is $2,000, the calculation starts off with your being responsible for 2/3 of the basic monthly obligation. Each parent's percentage share of daycare and health insurance costs for the child are then added in.
There is then an adjustment if each parent spends 20% or more of the overnights with the child - that's the number of nights the child spends with you under the time-sharing plan in place. It's a bit more complicated to explain this calculation, but there are detailed instructions on the Worksheet. Basically, the parent paying child support will pay less, the more overnights they spend with the child.