Child support assessment

How we assess the amount of child support you need to pay or receive. The formula we use to work it out is in Australian law.

You need to know

The assessment formula

The child support assessment formula looks at circumstances to work out how child support should be paid.

Read more about the child support assessment formula


To be eligible for a child support assessment you meet residence rules and be the legal parent or non-parent carer of the child.

Read more about eligibility

How your percentage of care affects your child support payments

Our child support assessment considers each parent or non-parent carer’s care of the child. This is their percentage of care.

Read more about how your care arrangements affects your child support

How your income affects your payment

We consider each parent’s income equally when we make a child support assessment. We don’t use income from non-parent carers.

Read more about income considered when calculating child support

Basic formula

This formula is for parents with only 1 child support assessment.

Read more about working out payments using the basic formula

Assessment period

A child support assessment period can be up to 15 months.

Read more about the assessment period

Your child is turning 18 and is still at school

Normally child support stops when your child turns 18.

Read more about your child support assessment when you child turns 18

Assessment for same-sex parents

You and the other person on your child support assessment application must be the child's parent or non-parent carer.

Read more about child support assessment for same-sex parents

Assessments for non-parent carers

If you care for a child and you're not their parent, you may be able to get child support from one or both parents.

Read more about a child support assessment for non-parent carers

Parents with 2 or more assessments

We work out how much child support you pay or receive if you have 2 or more families from past relationships.

Read more about parents with 2 or more child support assessments

Assessments for parents with second families

If you have children from a new family, we reflect this in your assessment.

Read more assessments with second families

Fixed and minimum assessments

We can base some child support assessments on a fixed rate or a minimum rate.

Read more about minimum and fixed assessments

Residence rules

We can make a child support assessment if at least 1 parent lives in Australia.

Read more about residence rules

Parenting plans

A parenting plan is a written agreement with the other parent. It sets rules for things like how much time the children will spend with each parent.

Read more about parenting plans

What ends an assessment

There are a few reasons why a child support assessment will end.

Read more about events that end your child support assessment


Check if you're eligible before you start your claim.


  • apply for a child support assessment
  • we'll assess your application and let you know the outcome



Choose a collection option

The person who will receive child support can choose how the paying parent pays them.

Read more about collection options

Private Collect

This is where you and the other parent make and receive payments directly between you. It’s for parents who don’t need much help from us to agree on a plan.

Read more about Private Collect payments

Child Support Collect

This is where we collect and transfer child support payments for you.

Read more about Child Support Collect payments

Self employed parents

If you're self employed and pay child support through us, you can use most payment methods.

Read more about self employed parents with a child support assessment

Changes of circumstances

We need to know about changes that could affect your child support.

Read more about how a change of circumstances can affect your child support

Changing your assessment in special circumstances

We can change your child support if we’re satisfied there are special circumstances and the change would be fair to both parents and the child.

Read more about changing your assessment in special circumstances

Child support and military deployment

When you leave Australia on military deployment you need to tell us your new details. This is so we can make sure your child support is still accurate.

Read more about responsibilities when you are being deployed

Child support if you go to prison

You must tell us if you go to prison. This is so we can make sure your child support is accurate.

Read more about how we assess your child support if you go to prison

While living outside Australia

In some cases we can help separated parents with child support arrangements for their children when one parent lives in another country.

Read more information about child support when parents and children live overseas.


Percentage estimator

The care estimator is a tool that calculates your care percentage.

Read more about the child support care percentage estimator

Fact sheets in your language

We have information about child support in many languages.

Read more about the child support information we have in your language

Payment and Service Finder

Find, estimate and compare payments and services you may be eligible for. You can also work out what a change in circumstance might mean for the payments and services you currently receive from us.

Start using Payment and Service Finder

Manage your money


We’ve got advice and tools to help you with budgeting, borrowing and credit, and managing debt.

Read about how to manage your money

Regular deductions using Centrepay

You can use our free and voluntary service to pay bills as regular deductions from your Centrelink payments.

Read more about how Centrepay works

Page last updated: 8 January 2018