How Do I Modify Child Support in Florida?

You modify Florida child support by filing a supplemental petition for modification in the circuit court that entered your order and proving a substantial change in circumstances. The guidelines themselves supply that change when the new calculation differs from your current amount by at least 15 percent or $50, whichever is greater.

Child Support Changes Only by Court Order

The single most expensive mistake Florida parents make with child support is handling a change privately. A parent loses a job, the two of you agree on a lower number over text, payments drop, and everyone moves on. Legally, nothing changed. The old order is still the order, and the difference is piling up as arrears.

Florida law is unusually blunt about this. Under section 61.14(6) of the Florida Statutes, every unpaid installment of support becomes a final judgment by operation of law, and that judgment is final as to everything that accrued up to the time a party files a motion to modify. A court may modify only the installments that come due after the filing date. Past-due support cannot be forgiven retroactively, no matter how reasonable the private arrangement seemed at the time.

The mirror image of that rule is the reason to move quickly: section 61.14(1)(a) lets the court make a modification retroactive to the date you filed your supplemental petition. Every month you wait is a month at the old number that you cannot get back.

One more rule catches parents off guard. Section 61.14(7) says the proof required to modify a support number the two of you agreed to in a settlement is exactly the same as the proof required to modify a number a judge imposed. Agreeing to an amount does not lock it in, and it does not make it harder to change either.

What Counts as a Substantial Change

Florida courts ask whether the change in circumstances is substantial, material, involuntary, and permanent. Each of those words does work:

• Substantial and material — big enough to matter to the guideline calculation, not a minor swing in overtime or a temporary dip in commissions.
• Involuntary — a layoff, a disability, a plant closing. Quitting a job or taking a lower-paying position by choice generally will not reduce your obligation.
• Permanent — ongoing rather than a short gap you are expected to recover from.

The involuntary requirement is where most reduction requests fail. Section 61.30(2)(b) allows a court to impute income to a parent it finds voluntarily unemployed or underemployed, based on that parent’s recent work history, occupational qualifications, and prevailing earnings in the community. A 2021 amendment put guardrails on imputation: the court generally may not impute from income records more than five years old at the time of the hearing, and may not impute at a level a parent has never actually earned unless that parent is newly degreed, licensed, or certified. But if a parent simply refuses to provide financial information, the statute creates a rebuttable presumption that the parent earns the median income of year-round full-time workers reported by the U.S. Census Bureau — which is rarely the number that parent was hoping for.

Section 61.30(2)(c) carves out one situation explicitly: incarceration may not be treated as voluntary unemployment when a support order is being established or modified.

Changes that commonly support a modification include a genuine loss of income, a significant raise for either parent, a child aging out, the birth of a child the obligor now supports (which section 61.30(12) allows to be raised only when someone is seeking an increase, never as a reason to cut an existing award), new or changed daycare costs, a change in who provides health insurance, and a child developing special needs.

Time-sharing deserves its own mention, because in Florida it is baked into the math. When a parenting plan gives each parent a substantial amount of time — defined in section 61.30(11)(b)8. as at least 20 percent of the overnights in a year — support is computed with the gross-up formula rather than the standard one, which usually lowers the transfer between households. So a real change in the overnight schedule is a real change in support. And section 61.30(11)(c) closes the loop the other way: if a parent whose support was reduced for time-sharing then fails to regularly exercise that schedule, the failure is itself a substantial change, and the modification is retroactive to the date the parent first stopped showing up.

The 15 Percent or $50 Rule

There is a numerical shortcut built into the statute. Section 61.30(1)(b) says the guidelines may themselves prove a substantial change in circumstances, but only if the difference between the existing monthly obligation and the amount the guidelines now produce is at least 15 percent or $50, whichever amount is greater.

Read that carefully, because the arithmetic surprises people. On a $300 monthly order, 15 percent is $45, so the $50 floor controls and you need a $50 gap. On a $900 order, 15 percent is $135, so the percentage controls and $50 is nowhere near enough. Always run both numbers and use the larger one.

That is why the practical first step in any modification is not a phone call to the courthouse — it is running a fresh guideline calculation with current figures for both parents: incomes, allowable deductions, daycare, health insurance premiums for the child, and the actual overnight split. If the new number is not far enough from the old one, filing is usually a waste of a filing fee.

Once you are in front of the judge, the guideline result is presumptively correct. The court can vary from it by up to 5 percent without explanation, and by more than 5 percent only with a written finding explaining why the guideline amount would be unjust or inappropriate. Section 61.30(11)(a) lists the factors that justify going outside the range — extraordinary medical or educational expenses, the child’s independent income, seasonal income swings, special needs, and an order that would take more than 55 percent of a parent’s gross income, among others.

Filing a Supplemental Petition for Modification

The document is a Supplemental Petition for Modification of Child Support, and it is filed in the same circuit court case that produced the existing order — you are reopening your case, not starting a new one. Section 61.14(1)(a) also permits filing in the circuit where either party now resides.

• File the supplemental petition in the original case, stating what changed, when it changed, and what you want the new amount to be.
• Attach a current financial affidavit. Section 61.30(14) requires it, and requires that it be served at the same time as the petition. The other parent must file one too, no later than 72 hours before any hearing on finances.
• Serve the other parent. A supplemental petition is served like an original pleading, with a summons — not simply emailed to opposing counsel.
• Exchange financial discovery, which in a support case usually means pay records, tax returns, and proof of daycare and insurance costs.
• Attend mediation. Miami-Dade routinely refers contested family matters to mediation before a hearing, and a great many modifications settle there.
• Get the new order entered. If you settle, the agreement is submitted for the judge’s signature; if you do not, an evidentiary hearing follows.

Two timing notes. First, the retroactivity in section 61.14(1)(a) runs from the filing date and is discretionary — the statute says the court may modify retroactively “as equity requires,” so file first and negotiate second. Second, if income withholding is in place, the new amount does not reach your paycheck until an amended income deduction order goes to the employer; the order alone does not change the deduction.

The Free Route: Asking the Department of Revenue to Review

If your case is handled by the Florida Department of Revenue Child Support Program, you can ask the agency to review the order instead of hiring a lawyer to file. According to the Department, you may qualify for a review when your current order will not end within six months of the request, and either the order has not been reviewed or changed in the last three years, or you can show a large change in your life — for example a significant income change or a child who becomes disabled.

The threshold is different on this track, and it is friendlier. Under sections 61.14(1)(d) and 61.30(1)(c), when the Department reviews an order as required by section 409.2564(11) and the current amount differs by at least 10 percent, but not less than $25, from the guideline amount, the Department pursues a modification without any requirement to prove a change in circumstances at all. No substantial change, no involuntariness, no permanence.

The trade-off is speed and scope. The Department says a review and change generally takes about six months, it reviews the number rather than advocating for either parent, and it does not address time-sharing, parental responsibility, or anything else in your parenting plan. If the support number is the only thing you want adjusted and you are not in a hurry, it is a sensible first call. If the schedule is also changing, or the other parent’s income is complicated or hidden, court is the better forum.

Whichever route you take, remember section 61.14(9): the current support obligation for a child ends when that child turns 18 or the disability of nonage is removed, unless the order or the parties provide otherwise. Support can run to 19 for a child still in high school with a reasonable expectation of graduating before that birthday, but only if the order says so — which is worth confirming before a child’s senior year, not after. And ending current support never erases arrears.

Modifying Child Support in Miami-Dade County

Miami-Dade modifications are filed in the Eleventh Judicial Circuit, Family Division, at the Lawson E. Thomas Courthouse Center in downtown Miami. The Circuit’s Self-Help Program publishes a modification packet and lists the clerk’s filing fee for a modification as $50, with a $10 summons issuance fee and a $40 fee if the Sheriff serves the other parent. Those figures come from the Circuit’s published fee schedule and are worth confirming with the Clerk before you file, since court fees change.

Self-help staff can hand you the right forms and notarize them. What they cannot do is tell you whether your facts clear the substantial-change bar, whether a judge is likely to impute income to your ex, or how the overnight count in your parenting plan should be applied to the gross-up formula — and in a modification, those are the questions that decide the outcome.

Local practice matters too. Miami-Dade’s economy runs heavily on self-employment, tips, commissions, and seasonal work, and section 61.30(2)(a) sweeps all of it into gross income, defining business income as gross receipts minus the ordinary and necessary expenses required to produce that income. Modifications here often turn less on whether something changed than on proving what the other parent actually earns.

Arturo R. Alfonso P.A. has represented Miami-Dade parents in English and Spanish for 30 years, from Hialeah and Miami Lakes to Brickell, Kendall, and Cutler Bay. We handle modifications from both sides — parents who need an order reduced after a real loss of income, and parents who suspect the other side’s income has grown well past what the old order assumed. If you have been searching for a child support modification lawyer near me in Miami, schedule a consultation and we will run the guideline numbers before you spend anything on filing.

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