Family Law Advisors

Child Support Agreement vs Assessment: What's the Difference?

One is the government's standard formula. The other is something you and your ex-partner work out yourselves. Here's how to tell which fits your situation.

Most separated parents start out on the standard child support assessment without really choosing to - it's simply the default. A child support agreement is what you use instead, if you and your ex-partner would rather set your own terms.

What is a child support assessment?

A child support assessment is the standard calculation Services Australia performs, using a set formula based on both parents' incomes, the amount of care each parent provides, and the ages and number of children involved. It's the default arrangement - if you and your ex-partner don't set anything else up, this is what applies. Neither of you negotiates the figure directly; it's calculated for you.

What is a child support agreement?

A child support agreement is a private, written agreement between you and your ex-partner about how child support will be paid, instead of relying on the standard assessment formula. There are two types - a limited agreement, which has to be based on an existing assessment and either of you can end after three years, and a binding agreement, which doesn't need to be based on an assessment at all but requires independent legal advice for each of you before it takes effect. Our child support agreement page covers both types in full.

Side by side

Assessment Agreement
Who sets the amount Services Australia, via a standard formula You and your ex-partner, by mutual agreement
Is it the default? Yes - applies automatically if nothing else is set up No - you have to actively set one up
Requires independent legal advice? No Only for a binding agreement - not a limited one
How flexible is it Recalculated as circumstances change, on their formula Whatever terms you both agree to include

Which one do I need?

If you're happy with a standard, formula-based figure and don't need anything more tailored, the assessment already applies to you by default and there's nothing to prepare. If you and your ex-partner want to agree your own arrangement - a different amount, a different payment structure, or terms the formula doesn't cover - a child support agreement is the right product. If you're specifically looking to move away from an assessment you're already on, our opting out of the assessment page walks through exactly how that switch works.

Questions people ask about child support agreements and assessments

Can we just opt out of the child support assessment entirely?
Yes - that's exactly what a child support agreement lets you do, replacing the standard assessment with your own privately agreed arrangement. See our full explainer on opting out of the assessment for how that works and what's involved.
Do we need a lawyer each to set up a binding child support agreement?
Yes, for a binding agreement specifically - that's a legal requirement, not optional. Each of you needs independent legal advice before signing for it to take effect. A limited agreement (which has to be based on an existing assessment) doesn't require this, but is also easier to end.
Is a child support agreement better than just using the assessment?
It depends what you both want. The assessment is simpler - Services Australia calculates a figure using their standard formula, and you don't need to agree on anything beyond your basic details. A child support agreement takes more upfront effort to put together, but gives you control over the amount and how it's paid. Neither is objectively better - it comes down to whether you both want that extra flexibility.

Not sure which one applies to you?

Tell us your situation and we'll point you the right way

Not sure whether you need an agreement at all? Tell us what's going on.

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