State Self-Employment Tax: NJ, Idaho, and Minnesota Compared
No state imposes a separate "self-employment tax." Self-employment income is taxed through each state's regular income tax. New Jersey applies graduated rates from1.4% to 10.8%, Idaho charges a flat 5.3%, and Minnesota uses graduated rates from 5.3% to 9.8%. These state income taxes are in addition to the federal 15.3% self-employment tax and federal income tax.
How states tax self-employment income
The federal self-employment tax (15.3% covering Social Security and Medicare) is a federal-only tax. States do not have their own version of this payroll tax for self-employed workers. Instead, states tax self-employment income through their regular income tax systems.
Your state income tax on self-employment earnings works the same as state income tax on any other type of income. However, important details vary by state: how the state defines taxable income, whether it conforms to federal deductions, and whether it has a graduated or flat rate structure.
New Jersey: 1.4% to 10.8%
New Jersey imposes a graduated income tax with rates ranging from 1.4% to10.8%. For single filers, the 2026 brackets are:
| Income Range | Rate |
|---|---|
| $0 - $20,000 | 1.4% |
| $20,000 - $35,000 | 1.8% |
| $35,000 - $40,000 | 3.5% |
| $40,000 - $75,000 | 5.5% |
| $75,000 - $500,000 | 6.4% |
| $500,000 - $1,000,000 | 9.0% |
| $1,000,000 - and above | 10.8% |
Key characteristics of NJ for self-employed workers:
- NJ has no standard deduction. Instead, it uses personal exemptions (typically $1,000 per exemption), resulting in a smaller pre-tax reduction than states that conform to the federal standard deduction.
- NJ calculates tax using its own gross income definition, which does not start from federal AGI. This means NJ may not recognize certain federal deductions.
- NJ does not conform to the OBBBA deductions. Self-employed workers who receive tips would not benefit from the federal tips deduction at the NJ level regardless (since it requires W-2 employment at the federal level anyway).
Idaho: flat 5.3%
Idaho uses a flat income tax rate of 5.3% on all taxable income for 2026. This simplifies the calculation significantly for self-employed workers: after deductions, multiply taxable income by 5.3%.
Key characteristics of Idaho for self-employed workers:
- Idaho conforms to the federal standard deduction, so single filers get the same $16,100 standard deduction at both the federal and state level.
- The flat rate means your marginal rate equals your effective rate (before the standard deduction). There is no bracket management needed.
- Idaho's rate has been declining in recent years, making it increasingly competitive for self-employed workers compared to neighboring states.
Minnesota: 5.3% to 9.8%
Minnesota has a graduated income tax with four brackets. For single filers in 2026:
| Income Range | Rate |
|---|---|
| $0 - $33,310 | 5.3% |
| $33,310 - $109,430 | 6.8% |
| $109,430 - $203,150 | 7.8% |
| $203,150 - and above | 9.8% |
Key characteristics of Minnesota for self-employed workers:
- Minnesota's top rate of 9.8% is one of the highest state income tax rates in the country, applying to income above $203,150.
- Minnesota does not conform to the OBBBA deductions. The state's IRC conformity date predates the OBBBA, so any federal tips or overtime deductions must be added back on the Minnesota M1 return.
- Minnesota uses its own standard deduction amount, indexed separately from the federal standard deduction.
- Minnesota fully exempts Social Security benefits from state income tax, which can benefit self-employed retirees who have both SE income and Social Security income.
Side-by-side comparison
| Feature | New Jersey | Idaho | Minnesota |
|---|---|---|---|
| Tax structure | Graduated (7 brackets) | Flat | Graduated (4 brackets) |
| Rate range (single) | 1.4% - 10.8% | 5.3% | 5.3% - 9.8% |
| Standard deduction | None (personal exemptions) | Federal conformity ($16,100) | Own indexed amount |
| OBBBA conformity | No | Varies by provision | No |
At moderate self-employment income levels (around $70,000 for single filers), Idaho's flat 5.3% will produce a lower state tax than either New Jersey or Minnesota. At lower income levels, New Jersey's lowest bracket (1.4%) is the cheapest, but that advantage disappears quickly as income rises through the graduated brackets.
Reducing your state tax burden
Regardless of which state you are in, self-employed workers can reduce their state income tax by:
- Maximizing legitimate business deductions on Schedule C, since most states start their income calculation from federal figures (or calculate net SE income similarly)
- Contributing to tax-deferred retirement accounts (SEP-IRA, Solo 401k), which reduce taxable income at both the federal and state level in most states
- Tracking the half-SE-tax deduction, which reduces federal AGI and may flow through to reduce state taxable income (depending on the state's starting point)
For state-specific paycheck and tax calculations, use the New Jersey paycheck calculator, Idaho paycheck calculator, or Minnesota paycheck calculator.