Plan Your Custody Schedule with Clarity

Divide the total overnights one parent has in a year by 365, then multiply by 100. That is it. If Parent A has 182 overnights, the math is (182 ÷ 365) × 100 = 49.9%. Courts in every U.S. state use this overnight method because it is objective, verifiable, and easy to enforce.

True 50/50 means roughly 182 or 183 overnights per parent per year. The alternating-weeks, 2-2-5-5, and 3-4-4-3 schedules all produce that count. In practice, most courts and attorneys treat anything between 45% and 55% as "substantially equal," and the child support math tends to follow that same definition.

Every-other-weekend is still the most traditional arrangement, giving the non-primary parent about 14% of the year. Adding a midweek overnight pushes that to roughly 28%. Over the past decade, though, family courts have moved steadily toward 50/50 arrangements, and in many states a 50/50 schedule is now the presumptive starting point unless one parent raises specific concerns.

A 2-2-5-5 is a 50/50 schedule that runs on a 14-day cycle: 2 days with Parent A, 2 days with Parent B, 5 days with Parent A, 5 days with Parent B. The appeal is that no one ever goes more than five days without seeing the child, which matters a lot for younger kids. The trade-off is more exchanges (four per cycle), so parents need to live close to each other for it to work.

A 3-4-4-3 is another 50/50 rotation, but with longer blocks than the 2-2-5-5. Week one, Parent A has 3 days and Parent B has 4. Week two, Parent A has 4 and Parent B has 3. Because handoff days are consistent from week to week (say, always Thursday and always Monday), it tends to be easier to plan around a 9-to-5 work schedule than the 2-2-5-5.

The classic Friday-evening to Sunday-evening every-other-weekend works out to 52 overnights a year (26 weekends × 2 nights), which is 14.2%. If the order extends the weekend to Monday morning, the count jumps to 78 (21.4%). Adding a weekly midweek overnight brings it up to 104 nights or 28.5%.

Holiday provisions override the base rotation and can shift the real annual percentage by two or three points in either direction. If one parent gets an extra 3-week summer block and a bigger chunk of winter break, that alone is about 28 extra overnights, which turns a 70/30 schedule into closer to 62/38 for that year. Run the full count, including holidays and summer, before assuming the base schedule is your final number.

Yes, and often significantly. In most states, crossing a shared-custody threshold (usually somewhere between 30% and 40% of overnights) triggers a different child support formula that reduces the paying parent's obligation. A few percentage points around that cliff can change support by hundreds of dollars a month, which is why running the numbers before you agree to a schedule matters so much.

The calculator gives you a mathematically accurate percentage based on whatever overnights you enter. Your attorney or mediator can use that number as a starting point for negotiations, and many do. But the calculator is not legal advice and is not a substitute for professional guidance on custody matters. Your state may also use different counting conventions for edge cases, so always verify with a family law attorney in your jurisdiction before relying on any number in a filing.

For kids under three, most child development researchers recommend shorter, more frequent contact rather than long overnights away from the primary caregiver. A common starting point is a few weekday visits (2 to 4 hours each) plus a short weekend overnight, gradually building up as the child gets older and more secure. By age 3 or 4, most children can handle a 2-2-3 or 2-2-5-5 rotation if both parents live close and the transitions are calm.