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Shared Custody Child Support Calculator

See how 50/50 and custom custody splits affect monthly child support. Includes the offset/cross-credit method and schedule comparison tool.

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Higher earner
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children
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Monthly premium for children
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50/50 Shared Custody Support
$232/mo
Base Support (No Shared)$2,784/mo
Parent 1 Obligation$812/mo
Parent 2 Obligation$580/mo
Net Transfer$232/mo
In 50/50 custody, the higher earner still pays if incomes differ. Net transfer: $232/mo from Parent 1 (higher earner).
Advanced Calculator

Cross-credit offset method, custody percentage impact line chart with 50/50 marker, common schedule comparison, and year-by-year projection.

+ Open Advanced Calculator
Shared Custody Inputs
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Cross-Credit Result
$394/mo net transfer
PayerParent 1
P1 Obligation$1,013/mo
P2 Obligation$619/mo
Schedule50% / 50%
Parent 1 Custody % vs. Net Transfer Amount
50/500%10%20%30%40%50%60%70%80%90%100%$0$506$1K$1.5K$2K
P1 Custody %Net TransferDirectionAnnual
30%$1,046/moP1 pays$12,555
40%$720/moP1 pays$8,640
50% ← you$394/moP1 pays$4,725
60%$68/moP1 pays$810
70%$259/moP2 pays$3,105
80%$585/moP2 pays$7,020
Professional Simulator

Full P1/P2 income breakdown, detailed cross-credit calculation, transportation and activities costs, what-if scenarios, NPV, and 20-year lifetime projection.

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Parent 1 Income — Total: $100,000/yr
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Parent 2 Income — Total: $50,000/yr
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Custody & Costs
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Shared Custody Cross-Credit Analysis
$863/mo (Parent 1 pays)
Cross-Credit Calculation
Base support: $3,375/mo
P1 obligation: $1,125/mo
P2 obligation: $563/mo
Net transfer: $563/mo
Total Obligation
Net transfer: $563/mo
Health ins. (67%): +$200/mo
Transportation: +$100/mo
Annual extras: +$600/yr
Total: $863/mo
P1 Schedule50% / 50%
P1 Income Share66.7%
P1 Net After CS$6,152/mo
Annual Total$10,950

How Shared Custody Affects Child Support

In shared or joint custody arrangements, both parents provide direct financial support by covering expenses when the children are with them. The child support calculation adjusts to credit the non-custodial parent for their direct expenditures and prevents double-counting.

The Offset/Cross-Credit Method

Most states use an offset method for shared custody: each parent is assigned a theoretical obligation based on their income share, then that obligation is reduced by their own direct expenditures (reflected through time-share). The parent with the larger obligation pays the net difference to the other parent.

Parent 1 Theoretical Obligation = Base Support × P1 Income Share × P2 Time Share
Parent 2 Theoretical Obligation = Base Support × P2 Income Share × P1 Time Share
Net Transfer = |P1 Obligation − P2 Obligation|
Higher obligation parent pays the net transfer amount

Does 50/50 Custody Eliminate Child Support?

Not automatically. Even in true 50/50 custody, the higher-earning parent typically still pays support. This is because the children's needs remain based on the combined household standard of living, and the lower earner needs assistance to provide equivalent housing, food, and activities during their time.

Example — 50/50 Custody

Parent 1: $7,000/mo. Parent 2: $5,000/mo. Two children. Exactly 50/50 custody.

Combined Income$12,000/mo
Base Support~$2,340/mo
Parent 1 Income Share58.3%
Parent 1 Obligation × 50% time$682/mo
Parent 2 Obligation × 50% time$487/mo
Net Transfer (P1 → P2)$195/mo

Even at 50/50, Parent 1 pays $195/mo because they earn more.

Frequently Asked Questions

Not necessarily. In 50/50 custody, the higher-earning parent typically still pays support to equalize the children's standard of living in both homes. The offset method calculates each parent's theoretical obligation and the higher-earning parent pays the net difference. In some states, courts may waive support entirely in 50/50 arrangements if incomes are very close, but this is the exception rather than the rule.
The threshold varies by state. Florida uses 73 overnights (20%). Colorado and California use 146 overnights (40%). Many other states use 30-40% time-share. Below the threshold, standard child support applies without adjustment. Above it, the offset method kicks in. This threshold is one reason custody disputes often become contentious — crossing a threshold can mean hundreds of dollars per month difference.
An overnight is generally counted when the child sleeps at a parent's home. Courts count the actual overnights in a proposed parenting plan or over the past year. Holidays, school breaks, and summer vacations all count. Some states use a percentage-of-time calculation rather than actual nights. If you have a flexible or varying schedule, courts may average over a period of time.
Parents can agree to waive or reduce child support, but courts must approve any agreement that deviates from guidelines. Judges will evaluate whether the arrangement serves the children's best interests. A zero-support agreement in 50/50 custody is more likely to be approved when parents have very similar incomes. Courts are skeptical of arrangements that leave children with inadequate support in one home.
A change in custody is typically grounds for modification of child support. If the custody change is significant enough to cross a calculation threshold (e.g., from 20% to 40%), the support amount could change substantially. You must file for modification with the court — informal agreements between parents are not legally binding and cannot be enforced or credited. Document all custody changes in a court order.

Related Calculators

General Child Support
Income Shares model for standard custody
Florida Child Support
FL shared parenting adjustment at 73 nights
California Child Support
CA formula with time-share variable (H%)
Modification Calculator
Custody change → new support amount
Texas Child Support
TX Standard and Expanded Possession Orders
New York Child Support
NY 50/50 offset in CSSA context