If I had a dollar for every time a client told me what they thought child support was going to be based on what their neighbor said, I could retire. (I am not retiring. But I could.)

Child support in Tennessee is not a negotiation. It is not based on what seems fair to either parent. And it is definitely not based on what happened to your neighbor.

It is based on a formula. And at my office, one of the things we do at the initial consultation is sit down and actually walk through that formula together. I want my clients to understand the why behind the number, not just accept a figure on a piece of paper. And I want them to be able to run it themselves when circumstances change.

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The Income Shares Model

Tennessee uses what is called the income shares model for child support. The idea is straightforward: the child should receive the same proportion of parental income they would have received if the family had stayed together.

To calculate support, you start with both parents’ gross incomes. You add them together. You look at the number of children. The guidelines produce a presumptive support amount based on that combined income. Then each parent contributes their proportionate share.

The parent who pays support is generally the one with less parenting time. The calculations reflect how much time each parent actually has the child.

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What Goes Into Income

Tennessee casts a wide net on income. Wages, salaries, commissions, bonuses, self-employment income, rental income, investment returns. The guidelines are designed to capture what a parent actually earns, not just their W-2.

Gig economy income counts. Venmo transfers that look like income count. If you are working under the table, the court can impute income based on your earning capacity rather than what you report. (I have seen this happen. It does not go well for the person trying to hide money.)

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Why You Should Know How to Run It Yourself

The state of Tennessee has a child support calculator available online. It is the same tool attorneys use. I encourage every client to bookmark it.

Here is why: life changes. Your income changes. Your ex’s income changes. Parenting time shifts. Children age out. Every one of those events is a potential reason to revisit the support number. If you know how to run the calculation yourself, you can evaluate whether a modification is worth pursuing before you spend money on an attorney to tell you the same thing.

Knowledge is leverage. In this case, it is also free.

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Deviations from the Guidelines

The presumptive amount is not always the final amount. Courts can deviate from the guidelines when there is a good reason. Extraordinary medical expenses, educational costs, or special needs of the child can justify deviation. So can a very high or very low combined income.

But deviations require justification on the record. A judge cannot just pick a different number because one parent asked nicely. There has to be a reason, and it has to be documented.

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Lawyer Bill’s Advice

Child support is math, not a feeling.

But the math depends on numbers that are easy to fudge if nobody is paying attention.

Learn how the calculator works. Run it yourself when things change.

And if the number you are paying or receiving does not seem right, ask someone who knows the formula before you just accept it.

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If you have questions, reach out to William W. Jones IV at midsouthdivorce.com/ask-lawyer-bill/.

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About the Author: William W. Jones IV is a Memphis family law attorney, Rule 31 Listed Family Mediator, and Super Lawyers selectee every consecutive year from 2014 through 2025. Licensed in Tennessee (BPR 022869) and Mississippi (BPR 100707), he practices at The Jones Law Firm, 5100 Poplar Ave, Suite 708, Memphis, TN 38137. Call (901) 761-5353 or visit midsouthdivorce.com.