School Year Custody Calculator

Enter school-year custody details

Number of children

Used for the summary heading.

School-year start date

First counted overnight in this planning window.

School-year end date

Last counted overnight in this planning window.

School-night weekday pattern

Sun

Mon

Tue

Wed

Thu

Fri

Sat

Default school nights are Sunday through Thursday.

Parent A school-night overnights per 14 days

Example: 5 of 10 school nights in a two-week cycle.

Parent A non-school-night overnights per 14 days

Use weekend or break nights not counted as school nights.

Parent A holiday or vacation overnights

Add school-year holiday adjustments assigned to Parent A.

Parent A closure or in-service overnights

Include snow days, closures, or teacher in-service days.

Monthly education cost

Tuition, books, supplies, fees, tutoring, or meals.

Monthly activity cost

Sports, clubs, arts, school events, and extras.

Parent A education cost share (%)

Percentage of education costs paid directly by Parent A.

Parent A activity cost share (%)

Percentage of activity costs paid directly by Parent A.

Parent A transportation share (%)

Share of exchange travel costs covered by Parent A.

One-way exchange miles

Distance from one home to the exchange point.

Exchanges per month

Average monthly handoffs during the school year.

Mileage rate per mile

Use your own fuel or mileage estimate.

Monthly support paid to Parent A

Enter a negative amount if Parent A pays support.

Example data table

Example input	Sample value	Example output	Sample result
School-year dates	Aug 20, 2026 to Jun 5, 2027	Total overnights	290
School-night pattern	Sun, Mon, Tue, Wed, Thu	Total school nights	207
Parent A school nights per 14 days	5	Parent A regular school-night overnights	103.5
Parent A non-school nights per 14 days	2	Parent A regular non-school-night overnights	41.5
Holiday overnights for Parent A	10	Parent A adjusted overnights	157.0
Closure overnights for Parent A	2	Parent A percentage	54.14%
Monthly education and activity costs	$400 and $180	Combined school-year cost pool	$7,531.91

Formula used

This planner uses proportional school-night and non-school-night allocation, then adds manual adjustments for holidays and closures.

Total overnights = inclusive days between start and end dates.
School nights per 14 days = selected school-night weekdays × 2.
Regular Parent A school-night overnights = total school nights × (Parent A school-night overnights per 14 ÷ school nights per 14).
Regular Parent A non-school-night overnights = total non-school nights × (Parent A non-school-night overnights per 14 ÷ non-school nights per 14).
Adjusted Parent A overnights = regular school-night overnights + regular non-school-night overnights + holiday overnights + closure overnights.
Custody percentage = adjusted parent overnights ÷ total overnights × 100.
Transportation pool = exchanges per month × school-year months × one-way miles × 2 × mileage rate.
Parent direct share = education pool share + activity pool share + transportation pool share.
Net cash position for Parent A = support transferred to Parent A − Parent A direct share.

How to use this calculator

Enter the school-year start and end dates for the planning window.
Select which weekdays count as school nights in your routine.
Enter Parent A overnights for school nights and non-school nights in a standard 14-day cycle.
Add any school-year holiday, break, closure, or in-service overnights assigned to Parent A.
Enter monthly education, activity, and exchange cost assumptions.
Set Parent A direct share percentages for those costs.
Add monthly support transferred to Parent A, or enter a negative amount if Parent A pays.
Press the calculate button to show overnights, custody percentages, classifications, and cost estimates above the form.

Frequently asked questions

1. What does this calculator estimate?

It estimates school-year overnights, custody percentages, exchange counts, and shared costs. It is useful for planning routines and discussing logistics, not deciding legal rights.

2. Why separate school nights from non-school nights?

School nights usually affect homework, transport, bedtime routines, and attendance more than weekend nights. Splitting them gives a more realistic school-year picture.

3. Can I use it for joint custody plans?

Yes. Enter the repeating two-week pattern that best reflects your normal routine. The tool works for near-equal sharing, primary placement, or minority-time schedules.

4. Does this replace a court order?

No. Court orders, mediated agreements, and local rules always control. Use this calculator to compare scenarios and prepare better questions for professionals.

5. How are holiday and closure nights handled?

They are added manually to Parent A after the regular two-week pattern is estimated. This helps model school breaks, teacher days, and unusual scheduling events.

6. What if Parent A actually pays support?

Enter the monthly support amount as a negative number. The net cash position will then reflect money flowing out from Parent A instead of in.

7. Can I change the school-night weekdays?

Yes. You can check any weekday pattern that fits your school calendar. The calculator then counts those selected nights across the full date range.

8. Why are exports included?

CSV files help compare scenarios in spreadsheets. PDF files create a clean snapshot you can save, print, or share during planning discussions.