Model both sides
The best planning answer often comes from comparing scenarios, not maximizing one deduction in isolation.
Free tax planning tool
Married Filing Jointly vs. Separately Decision Lab
See the tax difference first, then isolate the deductions, credits, state rules, and non-tax cash-flow assumptions driving it.
No account required Educational, not individualized advice
Modeled joint tax
$123,608
$98,608 federal + $25,000 state
Modeled separate tax and entered cost
$134,068
$107,068 federal + $27,000 state + $0 other cash flow; both spouses use the standard deduction
Joint model advantage
$10,460
Positive advantage is not a filing recommendation
Not modeled: the 2026 high-income itemized-deduction limitation, NIIT, Additional Medicare Tax, capital-gain stacking, AMT, credit eligibility, community property, loss limits, IRA deductions, education items, or state-specific filing rules.
Review filing status before filingEducational estimate, updated August 23, 2026. Uses 2026 federal ordinary-income brackets and standard deductions, user-entered itemized deductions, credits, and flat effective state rates. The MFS scenario requires both spouses to use the same standard-versus-itemized method. It is not a complete joint or separate return.
How to use the result
Move from estimate to decision
Run alternatives, identify the assumptions driving the difference, and save the documents needed to validate the final treatment.
Check interaction effects
Income, deductions, credits, payroll, retirement, and state rules can move together.
Validate before filing
Use the result to focus review. Do not treat a screening model as a completed return.
Take the next planning step
Request a planning follow-up
Core results are free and ungated. Share your contact information only if you want Taxstra to follow up about the planning questions this tool surfaced.
Frequently asked questions
The calculator is intentionally explicit about what it does and does not decide.
Is married filing separately just half of a joint return?
No. Brackets are generally narrower, and multiple credits, deductions, community-property rules, and state treatments can change.
Does this provide student-loan advice?
No. The optional cash-flow input lets you place a separately calculated annual payment difference beside the tax result. It does not calculate a plan or recommend filing status.
Can spouses itemize differently?
Federal rules generally require both spouses to itemize if one spouse itemizes on a separate return. Validate the entered scenario before relying on it.