State guidelines are the first place you should look if you want to estimate child support for your family. The guidelines are contained in state law and are very difficult to read, even for lawyers and judges, who use specialized software to enter figures and calculate support. If you want the most detailed calculation, with tax consequences considered, you can hire a lawyer to run the numbers for you. However, most state courts provide online calculators that allow you to calculate support yourself. If your state doesn’t offer a calculator, alllaw.com has a simple calculator for every state. If your state has its own calculator, use that—it will get you a more accurate result.