In Texas, there is no fixed limit on how often child support can be modified. A parent can ask the court to change the amount every three years as a routine review, or at any time, including the day after an order is signed, if a material and substantial change in circumstances has occurred. Which path fits your situation determines what you have to prove and how quickly you should file.
The Three-Year Review
Either parent can request a review once at least three years have passed since the order was last entered or modified. This path does not require any particular life event; the passage of time is enough to trigger the review itself. The catch is at the back end. For a court to actually change the amount, the figure produced by a fresh guideline calculation has to differ from the current order by at least 20 percent or $100 per month, whichever is greater.1Office of the Attorney General. Frequently Asked Questions About Child Support
In practice: if your current order is $1,000 per month, the new calculation has to come in at $1,200 or higher, or $800 or lower, to clear the 20 percent threshold. If the order is $400, the $100 flat threshold applies because 20 percent of $400 is only $80. The gap is deliberate. It keeps parents from returning to court every three years over trivial differences.
Modification at Any Time for a Material and Substantial Change
The three-year wait does not apply when a parent can show a material and substantial change in circumstances affecting the child or either parent. Under this path, there is no minimum interval between modifications. You can file whenever a qualifying change happens, even if your order was signed last month.2State of Texas. Texas Family Code 156.401 – Grounds for Modification
Texas law does not spell out “material and substantial” with a checklist, which leaves the question to the judge. The parent asking for the change has the burden of proving it. Courts look for changes that are significant in scale, ongoing rather than temporary, and not something the parent engineered. A parent who quits a well-paying job to shrink a support obligation will not get a sympathetic hearing.
What Counts as a Material and Substantial Change
There is no exhaustive statutory list, but courts consistently recognize a handful of categories.
Income Changes
A significant shift in either parent’s income is the most common ground. Involuntary job loss, a major pay cut from a restructuring, or a disability that reduces earning capacity all qualify. A substantial increase in the paying parent’s income can justify a higher amount. A modest raise or a short gap between jobs usually will not.
The Child’s Needs
A child who develops a serious medical condition requiring expensive treatment is a textbook example. Changes in health insurance also qualify. If the parent carrying coverage loses it, or if premiums jump sharply, the court can adjust both the base support amount and the medical support obligation. Texas treats medical and dental support as separate obligations on top of the base payment, so a change in insurance can trigger its own modification.3Office of the Attorney General. Changes in Medical and Dental Coverage
Custody Changes
If the child’s primary residence shifts to the parent who had been paying support, the entire structure of the order no longer fits. This is one of the clearest grounds for modification.
Incarceration
A parent ordered to pay support who is incarcerated for at least 60 days can seek a modification of periodic payments through the court.2State of Texas. Texas Family Code 156.401 – Grounds for Modification One important exception: a court cannot grant a modification based on incarceration if the parent was convicted of an offense involving family violence or harm to the child. Release from incarceration is itself treated as a material and substantial change, so either parent can seek an adjustment when the paying parent gets out.
If you go through the Office of the Attorney General rather than filing your own case, the administrative review process uses a longer threshold of 180 days of incarceration before it will process a modification request.4Office of the Attorney General. Incarcerated Parents
Additional Children
When the paying parent becomes legally responsible for supporting children from another relationship, the guideline calculation accounts for those obligations and the court can adjust the payment.
How the Court Recalculates
Whichever path you use, the court recalculates support with the same guideline formula applied in the original order, using updated income numbers. Those percentages run from 20 percent of the paying parent’s monthly net resources for one child up to 40 percent for five, with specific brackets in between.5State of Texas. Texas Family Code 154.125 – Application of Guidelines to Net Resources As of September 1, 2025, the percentages apply only to the first $11,700 per month in net resources.6State of Texas. Texas Family Code 154.125 – Application of Guidelines to Net Resources The recalculated figure is what the court compares against your existing order to decide whether the three-year threshold has been met or whether a material change has produced a meaningfully different result.
How to File
You have two main options for starting a modification: filing in court on your own, or requesting a review through the Office of the Attorney General.
To file in court, you submit a Petition to Modify the Parent-Child Relationship with the same court that issued the existing order. The other parent then has to be formally served with a copy of the petition before the case can move forward.
If you have an open case with the Attorney General’s Child Support Division, you can submit a Request for Review online or by mail instead of filing your own lawsuit.7Office of the Attorney General. Support Modification Process After the review is approved, the OAG may schedule a negotiation appointment where both parents try to agree on a new amount. If they agree, the OAG drafts a new order for the judge to sign. If they do not, a judge decides at a hearing.8Office of the Attorney General. Modification Journey
The OAG route is usually cheaper because you avoid court filing fees, but it tends to be slower. The Attorney General’s office estimates that most modifications take at least six months from start to finish.8Office of the Attorney General. Modification Journey
Why Timing Matters More Than Frequency
How often you can file is one question. When you file is the one that actually controls how much money is at stake. Filing a modification does not pause or reduce your existing obligation. You have to keep paying the full amount under the current order until a judge signs a new one. If you stop paying or pay less because you assume the modification will go through, the shortfall becomes arrears.9Office of the Attorney General. Modify Child Support
Unpaid child support in Texas accrues interest at 6 percent per year. More importantly, Texas courts generally cannot make a modification retroactive to any date before the petition was filed. Every month you wait after a qualifying change is a month you owe at the old rate with no chance of a retroactive credit. If your income drops in January and you do not file until June, you owe the full original amount for those five months regardless of how the case turns out.9Office of the Attorney General. Modify Child Support
Texas law also prohibits courts from reducing child support arrears that have already accrued, even if both parents agree to the reduction. Once support goes unpaid, that debt is locked in. A modification can only help you going forward, so when a qualifying change happens, file as soon as you can.