You need to know both parties incomes (less allowed deductions), daycare expenses(for work or school purposes), and the cost of health insurance. Then read the last answer, and then see if a local lawyer provides for a free consultation. Remember, a $10.00 error in calculation on a single ten year old child can be worth $960.00. That's $10 times 12 months times 8 years. Love is grand, and a $10.00 error can be almost a Grand! If needed, Duval Co. legal aid is a great resource.
Florida has adopted child support guidelines by which there is a formula that takes into account both parent's incomes and allocates the needs of the child in acccordance with them. The court may depart upward or downward from the guidelines if there are exceptional circumstances such as a major illness, or special needs for a child, which would cause a possible upward modification. Downward modifications are rare, perhaps if the chldren have large trust accounts there could be such a modification. When calculating the support guidelines make sure you are using accurate information about your spouse's income, especially if your spouse is self employed or is in the restaurant business or some other business whre a lot of unreported cash can be made. When you go to court go for an income deduction order so the money is paid out directly to the court by your spouse's employer to the clerk of court and is then sent to you. There is a small charge for this, but for record keeping purposes it is well worth it should your spouse stop paying.