What changed
The One Big Beautiful Bill Act (OBBBA, Public Law 119-21), signed July 4, 2025, made most of the 2017 Tax Cuts and Jobs Act provisions permanent. For child support calculations in 2026, the key changes are:
Federal tax brackets (permanent)
The lower TCJA bracket rates (10%, 12%, 22%, 24%, 32%, 35%, 37%) are now permanent. Without OBBBA, brackets would have reverted to higher pre-2017 rates in 2026, which would have increased taxes and lowered net disposable income for both parents.
SALT cap changes
The state and local tax (SALT) deduction cap, which was $10,000 under TCJA, has been increased:
- $40,400 for most filers (single, HoH, MFJ)
- $20,200 for married filing separately
- Phases down to $10,000 for high-income filers (MAGI above $505,000)
This matters for California parents who itemize deductions. With property taxes and state income taxes, many Californians hit the SALT cap. The higher cap means more of their state taxes are deductible federally, which lowers federal tax and increases net disposable income.
Child Tax Credit
- Increased from $2,000 to $2,200 per child
- Phase-out: $200,000 for single/MFS, $400,000 for MFJ
- Now indexed for inflation going forward
Standard deduction
The larger standard deductions are permanent:
- Single/MFS: $15,000
- Head of Household: $22,500
- MFJ: $30,000
Impact on child support
The net effect for most parents:
- Lower federal taxes (permanent TCJA rates) = higher net disposable income
- Higher SALT cap = more deductions for California parents who itemize = slightly higher net
- Higher CTC = lower federal tax for parents claiming children
Higher net disposable income generally means higher child support for the higher earner and more total income in the guideline formula.
Our calculator uses 2026 OBBBA brackets
The Support Split calculator uses the actual 2026 federal brackets, California brackets, SALT cap rules, and CTC amounts as enacted by OBBBA. Every calculation reflects current law.