To change an existing Florida child support order when the other parent won’t agree, you file Florida child support modification Form 12.905(b), the Supplemental Petition for Modification of Child Support, in the same circuit court that entered the original order.1Florida Courts. Florida Supreme Court Approved Family Law Form 12.905(b) – Supplemental Petition for Modification of Child Support The petition travels with a financial affidavit and a child support guidelines worksheet, gets served on the other parent, and usually reaches a final order three to six months later depending on your court’s docket and whether the two of you can settle at mediation.
Confirm You Clear the Threshold Before You File
Florida law lets a judge modify child support when circumstances or the financial ability of either parent have changed since the last order.2Florida Legislature. Florida Code 61.14 – Enforcement and Modification of Support, Maintenance, or Alimony Agreements or Orders The form itself calls this a “substantial change in the circumstances of the parties” that is also in the child’s best interests.1Florida Courts. Florida Supreme Court Approved Family Law Form 12.905(b) – Supplemental Petition for Modification of Child Support
Substantial has a number attached to it. Run a fresh guidelines calculation using current income for both parents, then compare the result to the current order:
- If the order is less than three years old, the difference must be at least 15 percent or $50 per month, whichever is greater.3Florida Senate. Florida Code 61.30 – Child Support Guidelines, Retroactive Child Support
- If the order is more than three years old, the bar drops to 10 percent or $25.2Florida Legislature. Florida Code 61.14 – Enforcement and Modification of Support, Maintenance, or Alimony Agreements or Orders
The change should also be permanent and involuntary. Florida’s Child Support Program treats permanent as lasting more than a year, and involuntary as something that happened to you rather than something you chose, such as a long-term illness or a company-wide layoff rather than a decision to earn less.4Florida Department of Revenue. Florida Child Support Program – Changing Support Orders A brief unemployment spell that resolves in a few months rarely gets a judge’s attention.
If You Left or Downgraded a Job, Expect Imputed Income
When a parent is voluntarily unemployed or underemployed, Florida law lets the court impute income at that parent’s earning capacity based on recent work history, occupational qualifications, and prevailing wages in the community.5Florida Senate. Florida Code 61.30 – Child Support Guidelines, Retroactive Child Support The other parent carries the burden of showing the unemployment is voluntary and identifying what you could be earning. If you’re the one asking for a reduction, bring documentation that the drop in pay was outside your control: termination letters, medical records, job-search logs.
Documents That Go With the Petition
Form 12.905(b) does not travel alone. The form’s instructions require several companion filings, either with the petition or shortly after:1Florida Courts. Florida Supreme Court Approved Family Law Form 12.905(b) – Supplemental Petition for Modification of Child Support
- A Family Law Financial Affidavit. Use the Short Form, 12.902(b), if your gross annual income is under $50,000, or the Long Form, 12.902(c), if it’s $50,000 or more.6Florida Courts. Instructions for Florida Family Law Rules of Procedure Form 12.902(b), Family Law Financial Affidavit (Short Form)7Florida Courts. Florida Family Law Rules of Procedure Form 12.902(c) – Family Law Financial Affidavit (Long Form)
- Child Support Guidelines Worksheet, Form 12.902(e). This calculates the proposed amount from both parents’ combined net income, the number of children, and the time-sharing schedule. If you don’t yet know the other parent’s income, you can file the worksheet after you receive their affidavit.8Florida Courts. Florida Family Law Rules of Procedure Form 12.902(e), Child Support Guidelines Worksheet
- Notice of Social Security Number, Form 12.902(j), if not already filed in the case.
- Certificate of Compliance with Mandatory Disclosure, Form 12.932, filed within 45 days after the other parent is served unless both of you waive document exchange.
- A written settlement agreement, if the two of you have already resolved any of the issues.
Pull your supporting records before you start typing: recent pay stubs, tax returns, proof of any new health insurance costs for the child, documentation of changed time-sharing, and records of any disability or job loss. The financial affidavit asks you to itemize every source of monthly income and every category of monthly expense, so having the paperwork in front of you saves a second pass.
Filling Out Form 12.905(b)
You can download the current form from the Florida Courts website or pick it up at your Clerk of Court’s office. Enter the case number and county from the original order at the top. The petition must be filed in the same county that issued that order; filing in the wrong county means rejection or a transfer that adds weeks or months.1Florida Courts. Florida Supreme Court Approved Family Law Form 12.905(b) – Supplemental Petition for Modification of Child Support
The “Grounds for Modification” section is the heart of the petition. Describe what changed, when it changed, and why it is substantial. Specifics beat generalities. “My employer eliminated my position in March 2025 and I have applied to more than 40 comparable roles without an offer” gives a judge something to work with. “I lost my job” does not.
You then state the new monthly support amount you want. Take that number straight from the guidelines worksheet rather than picking what feels fair. Florida judges follow the statutory schedule, which derives a minimum support need from both parents’ combined net income and divides it in proportion to each parent’s share, with an adjusted formula once both parents have the child at least 20 percent of overnights.3Florida Senate. Florida Code 61.30 – Child Support Guidelines, Retroactive Child Support
Pay attention to the retroactivity question. Under federal law, each child support installment becomes a judgment the moment it comes due and cannot be retroactively reduced, no matter when your circumstances actually changed.9Office of the Law Revision Counsel. 42 USC 666 – Requirement of Statutorily Prescribed Procedures to Improve Effectiveness of Child Support Enforcement A court can modify support only forward from the date the other parent receives notice of your petition. File as soon as you know the change is real. Every month you wait is a month of arrearages no judge can later forgive.
Filing and Paying the Fee
File with the Clerk of the Circuit Court in the originating county. Most case types go through the Florida Courts E-Filing Portal at myflcourtaccess.com, though in-person filing at the clerk’s office is still available. The filing fee for a supplemental petition for modification of child support typically runs around $50, varying by circuit.10Clerk of the Circuit Court and Comptroller, Palm Beach County. Unified Family Court Fees If you can’t afford it, apply for a determination of civil indigent status through the clerk; a finding of indigency waives the filing costs.11Florida Legislature. Florida Code 57.082 – Determination of Civil Indigent Status
Serving the Other Parent
Once the clerk processes the petition, the other parent must be formally served. The clerk issues Form 12.910(a), Summons: Personal Service on an Individual, and a private process server or county sheriff hand-delivers the summons together with your petition.12Florida Courts. Florida Family Law Rules of Procedure Form 12.910(a) – Summons: Personal Service on an Individual You cannot serve the papers yourself, by mail, or by hand delivery.
The other parent then has 20 days to file a response. If they respond and disagree, and the two of you cannot settle, you file a Notice for Trial to get on the court’s calendar. If they don’t respond at all, you can ask the clerk to enter a default, though the judge still has to measure your proposed amount against the guidelines before signing a modified order.
Mediation and the Final Hearing
Many Florida circuits require you to try mediation before they’ll set a hearing date.13Thirteenth Judicial Circuit. Modification of Child Support Check with your local clerk or your circuit’s website to find out whether yours is one of them.1Florida Courts. Florida Supreme Court Approved Family Law Form 12.905(b) – Supplemental Petition for Modification of Child Support A neutral mediator works with both parents toward a voluntary agreement, which, if reached, is written up and submitted to the judge for approval.
If mediation fails or isn’t required, the case goes to a final hearing in front of a judge or general magistrate. Bring copies of your financial affidavit, your guidelines worksheet, and your evidence of the changed circumstance. The judge reviews both parents’ current finances, applies the guidelines, and either modifies the order or leaves it in place. Figure three to six months from filing to final order, longer if the other parent contests aggressively or the docket is crowded.
The Free Administrative Alternative
Form 12.905(b) is not the only route. If your case is handled through Florida’s Child Support Program (a Title IV-D case), either parent can ask the Department of Revenue to review the order at no cost. You submit updated financial information to the Program, which then collects the same from the other parent.4Florida Department of Revenue. Florida Child Support Program – Changing Support Orders
The Program uses the same guideline thresholds. If it concludes the order should change, a Program attorney handles the court action for court-issued orders, or the Program initiates its own administrative proceeding for orders it originally issued.14Florida Legislature. Florida Code 409.2563 – Administrative Establishment of Child Support Obligations If it decides the order shouldn’t change, it closes the review and you still have the option of filing Form 12.905(b) yourself. The administrative path is slower but free, which is worth weighing if cost is a factor and your case is in the IV-D system.