Shared expenses are one of the most reliable triggers of co-parenting conflict — not because the amounts are huge, but because the rules are fuzzy and the record-keeping is usually terrible. A simple shared expenses tracker fixes both.
This guide covers what counts as a shared expense, how Australian parents typically split them, what to do when one parent stops paying, and how good records support a Change of Assessment if you need one.
What counts as a "shared expense"?
Child support is supposed to cover the everyday costs of raising children — food, clothing, household bills, day-to-day school costs. It's not designed to cover every receipt.
Shared expenses, in practice, usually mean the extras parents agree (or are ordered) to split on top of child support:
- School fees, uniforms, textbooks, laptops, excursions, camps
- Medical, dental, optical, allied health, mental health (especially gap fees and non-Medicare items)
- Braces and orthodontics
- Sports, music, dance — fees, equipment, competitions
- Tutoring
- Significant travel related to the children
- Birthday parties, special-occasion costs (sometimes)
What's not usually shared (already covered by child support): - Routine food and household costs - Basic clothing - Daily transport - Utility bills
How to agree the split
Common approaches Australian co-parents use:
50/50 Simplest. Works when incomes are roughly similar.
By income proportion If Parent A earns $80k and Parent B earns $40k, split 67/33. Fairer when incomes are uneven, but requires agreeing each year.
Following the Child Support Income Percentage Use the income percentages from your Services Australia assessment. Matches the formula already used for the underlying child support.
By category Some families split medical 50/50, school by income percentage, and activities by who enrolled the child. Document whichever logic you choose.
Put the agreement in writing
Even a casual co-parenting relationship benefits from a one-page agreement that lists: - Categories considered shared - Categories considered not shared - Split method - Threshold above which prior consent is needed (e.g. "anything over $200 needs both parents to agree first") - How and when reimbursements happen (monthly transfer, app payment, etc.) - What happens if a payment is missed
Attach this to your parenting plan or store it with your records.
What to track per expense
For every shared expense: - Date - Amount - Category (school / medical / activity / other) - Which child - Who paid - Whether prior consent was given - Receipt or invoice attached - Agreed split - Amount owed by each parent - Whether reimbursed (and when)
A spreadsheet works. A co-parenting app like Bloom does it with photos of receipts and an automatic running balance.
When one parent won't pay
Stay calm and use the record. Steps usually look like:
1. Send the receipt and a written request. Make it specific: amount, what it was for, when due. 2. Follow up in writing once. Avoid escalation language. 3. If still no payment, decide whether it's worth pursuing. Many parents absorb small amounts to keep the peace and save the big push for significant items. 4. For larger or chronic non-payment, options include: - A Change of Assessment through Services Australia, citing high costs for the children that aren't being shared. - Mediation through a Family Relationship Centre (often free for first sessions). - Legal advice — community legal centres offer free initial advice. - Small claims for clear debts where there's a written agreement.
Don't withhold contact, child support, or the children in retaliation. It backfires legally and emotionally.
Using expense records in a Change of Assessment
If you're applying for a Change of Assessment under "high costs of the children" or "high costs of providing for a child's special needs", your tracker is the evidence. The Registrar wants: - A list of expenses with totals - Receipts or invoices - Evidence the costs are ongoing - Evidence the other parent isn't contributing (or only minimally)
A consistent, time-stamped tracker is far more credible than a folder of loose receipts.
Tax and FTB notes
- Shared expenses paid by you don't change your taxable income or your FTB.
- Money received from your co-parent as reimbursement isn't income — it's reimbursement.
- Keep records anyway. If Services Australia ever audits, you want a clean paper trail.
A weekly habit
End of the week, five minutes: 1. Photograph any new receipts for shared items. 2. Log them in your tracker. 3. Send the other parent anything outstanding. 4. Mark off anything that's been reimbursed.
Small, consistent, boring. Exactly what a good shared expenses tracker should be.