How to split child expenses with a co-parent
Updated October 12, 2026 · 3-minute read
Shoes, school trips, a dentist visit: shared costs come up every month. Splitting them goes smoother when three things are clear: what counts as shared, how you split it, and how you ask. This guide walks through each one, with simple examples.
1 · Know what counts as a shared expense
Many families share costs like these. What counts in your family depends on your agreement or order, so check yours.
- School fees, supplies and trips
- Doctor, dentist and pharmacy costs not covered by insurance
- Sports, lessons and other activities
- Childcare
2 · Agree on a split, and write it down
Some parents split every shared expense 50/50. Others use a different split, like 60/40. Whatever you use, write it down so both of you work from the same number.
| Expense | Split | You paid | Their share |
|---|---|---|---|
| Doctor visit | 50/50 | $118.40 | $59.20 |
| Soccer season | 60/40 (you 60%) | $200.00 | $80.00 |
Their share = what you paid × their percentage. $118.40 × 50% = $59.20. $200.00 × 40% = $80.00.
3 · Ask in writing, with the receipt
A short written request is easier to keep track of than a conversation. Include:
- What it was for and the date
- The amount you paid and their share
- A photo of the receipt
Then write down the date you asked. Lawyers often ask for the receipt and the date you asked, not just the receipt.
4 · Keep track of what's still owed
For each shared expense, a simple record answers four questions:
- Who paid, and how much?
- What is the other parent's share?
- When did you ask?
- Has it been paid back, and when?
Once a month, add it up: what each of you paid, what's been paid back, and what's still outstanding. A neutral total is easier to talk about than a list of complaints.
| Expense | Paid by | Amount | Status |
|---|---|---|---|
| Doctor visit | You | $118.40 | Asked Sept 17 · paid back Sept 25 |
| School supplies | You | $64.00 | Asked Sept 20 · not paid yet |
| Swim lessons | Co-parent | $90.00 | They asked Sept 22 · you paid back Sept 24 |
The doctor visit and the swim lessons are already settled, so they don't count. Still outstanding: half of $64.00 = $32.00 owed to you.
Common questions
Should I also log the expenses the other parent paid?
Yes. A record that includes both sides is easier to read and the totals stay fair.
What if an expense isn't paid back?
Keep the request, the receipt and the dates in your record. What to do next depends on your agreement or order. Ask a mediator or a family lawyer.
Do I need to keep paper receipts?
A clear photo is often enough to keep track. Keep the paper too if your agreement or your lawyer asks for it.
Doing this in CustodyBook
- Log the expense, keep the receipt: amount, who paid and a photo.
- Turn on "I asked my co-parent to pay their share" and the app keeps the date you asked.
- Reimbursement math to the cent, with the split you set.
- Mark an expense "Already reimbursed" when it's settled.
- Export a clean monthly PDF you can share with your lawyer.
What it doesn't do: CustodyBook does not calculate child support. It only adds up the shared expenses you log, with the split you choose.
Free for 7 days, then $14.99 once. No subscription.
