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How is the amount of child support decided?

If you make your own arrangement you and the other person decide together who will pay child support and how much. We call this a private agreement. 

You can ask us to manage the payments for you but you decide the amount. We call this a voluntary agreement.

If you would like us to decide who pays child support and how much, you can apply for a formula assessment.  

We cannot tell you the amount or who will pay until we have done this assessment.

Estimate the amount

You can estimate the amount of child support based on information you have.

Use our nights per year calculator to work out the percentage of time the child spends with each parent of carer. This information is needed when you estimate the amount.

Use our liability/entitlement calculator to estimate what formula assessment payments might be.  

Will I get child support?

You'll probably get child support when one of these is true:

  • you do not live with the other parent and you care for your child all or most of the time
  • you're caring for someone else's child
  • you're a grandparent or other non-parent relative caring for a child in your family.

Will I pay child support?

You'll probably pay child support when one of these is true:

  • you do not live with the other parent and they care for the child all or most of the time
  • someone who is not the parent cares for your child.

What if I share care with the other parent? 

We cannot always tell who will be a paying parent and who will be a receiving carer until we have assessed your circumstances.

Katie's formula assessment

Katie applied for the formula assessment. She and her ex-partner Brad are not in touch anymore so she filled out the application to the best of her knowledge.

She used the online calculator to work out what she might be entitled to receive based on her own living situation and what she thinks Brad earns. When they were together, Brad was earning about $60,000 per year.

Inland Revenue checks the information against what is on file for both Katie and Brad.

Katie is not aware that Brad's income has reduced and that he has a new baby. Katie's estimate is not accurate as she wasn’t aware of Brad's changes so the amount she expected will be lower.

Katie receives a letter of entitlement and Brad gets his notice of assessment the following week.

Harry's payment arrangement

Harry works odd jobs. He and his ex-partner agreed to do a formula assessment but now Harry is worried about his finances. He looks at his work schedule and sees that he probably won't be able to make his child support payment next month. 

Harry reads the IR 151 and sees he doesn’t meet the criteria to estimate his income.

He calls Inland Revenue to explain his work situation. While on the phone they are able to make a payment arrangement that ensures that he won't go into debt while he is not working. 

If he falls behind in payments in the future he can offer a repayment through myIR and, if Inland Revenue agrees, his payments could be reduced.

2 minutes
Child support liability or entitlement calculator

This suggests an amount based on care arrangements and both parents' incomes.

Go to this tool
5 minutes
Child support nights per year calculator

Work out how many nights per year a child is in your care.

Go to this tool