Custody Time Calculator - Calculator Academy

Select a common schedule or pick the nights of the week to determine the custody time and percentage.

Custody (Parenting) Time Calculator

Schedule Picker

Advanced (Days / %)

Pick a common schedule, or click days in the calendar to build your own. Then press Calculate.

Common Schedules

Click any night to toggle between Parent A and Parent B. Showing a 2-week cycle:

Parent A

Parent B

▸ State shared-parenting thresholds (tap to show)

State	Shared-custody threshold
Illinois	146 overnights (40%)
Wisconsin	25% parenting time
Indiana	128+ overnights
Maryland	92 overnights
Ohio	90 overnights
North Dakota	164 overnights
South Dakota	180 overnights
Utah	111+ overnights (joint)
California / Georgia	Sliding scale (no fixed threshold)
Texas / New York	Case-by-case

Related Calculators

Custody Time Formula

The following formula can be used to calculate the child custody (parenting) time percentage for one parent over a given period.

CTP = (D / T) * 100

Variables:

CTP is the custody time percentage
D is the number of days the child spends with one parent
T is the total number of days in the period being considered

To calculate the custody time percentage, divide the number of days the child spends with one parent by the total number of days in the period being considered. Multiply the result by 100 to convert the fraction to a percentage.

What Is Custody Time (Parenting Time Percentage)?

In this calculator, “custody time” means the share of time a child spends with one parent during a defined period (often called parenting time or timesharing). It is typically expressed as a percentage based on the number of days (or, in many parenting plans, the number of overnights) the child is with that parent divided by the total days in the period.

How to Calculate Custody Time?

The following steps outline how to calculate the Custody Time Percentage (CTP).

First, determine the number of days the child spends with one parent (D).
Next, determine the total number of days in the period being considered (T).
Next, use the formula from above: CTP = (D / T) * 100.
Finally, calculate the Custody Time Percentage.
After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge.

Number of days the child spends with one parent (D) = 20

Total number of days in the period being considered (T) = 30

Custody Time Percentage (CTP) = (20 / 30) × 100 = 66.67%