OnePageFree tool
Shared Expense Split Calculator
Add child-related expenses, choose 50/50, income-based, or a custom split, and see the reimbursement balance in your currency.
Reviewed August 12, 2026
Expense result updated. Parent B owes Parent A $17.50.
Total shared expenses
$205.00
Parent B owes Parent A
$17.50
How the math works
Even split vs. income-based split
Even (50/50)
Every expense is split down the middle regardless of who paid it. If Parent A paid $200 total and the fair share is $100 each, Parent B owes Parent A $100.
Custom percentage
Use the percentage written in an agreement or chosen for a specific category. The calculator applies the remaining percentage to the other parent automatically.
By income (pro rata)
Each parent's share is proportional to their income. If Parent A earns twice what Parent B does, Parent A's fair share of any expense is about two-thirds, not half.
For an ongoing expense log with receipts and a running balance, see OnePage's expense splitting features.
Need to agree on categories and reimbursement rules first? Download the shared child expense planning worksheet (PDF).
Method and limits
How the balance is calculated
Calculation method
For 50/50, each fair share is half of the combined expenses. For income-based splitting, a parent's share equals that parent's income divided by both incomes, multiplied by the expense total. A custom split applies your chosen percentage and assigns the remainder to the other parent.
Reimbursement balance
The calculator compares each parent's fair share with what that parent already paid. The difference shows who would reimburse whom so that the selected split is reached. Rounding may create a difference of one cent.
Privacy and storage
Expense names, amounts, and incomes stay in the current browser session. This page does not save receipts, create an account record, or send a payment request.
Limits and review
The calculator does not decide whether an expense qualifies under a support order, tax rule, or local law. The method was reviewed on August 24, 2026. Confirm the applicable category and split in your agreement or with a qualified professional.
FAQ
Questions, answered
Put the plan into practice
Save schedules, expenses, and messages in OnePage
These free tools create a planning snapshot. OnePage gives both parents a shared place to use the plan day to day.
More tools
Free tools for co-parents
Custody Schedule Generator
Build a visual parenting calendar from a preset or custom rotation.
Try itParenting Time Calculator
Count overnights and percentages for a full year or date range, with holiday overrides and manual totals.
Try itUS Holiday Schedule Generator
Assign major US holidays and custom dates, then preview the schedule year by year.
Try itLong-Distance Parenting Cost Calculator
Estimate annual travel costs and compare equal, income-based, or custom allocations.
Try itParenting Plan Generator
Turn practical agreements into a structured, ready-to-review parenting plan draft.
Try itTravel Consent Letter Generator
Create a printable child travel consent letter with trip, adult, and emergency details.
Try itChild Support Calculator Finder
Find the relevant jurisdiction guide and official child-support calculation resources.
Try it