Self-employment tax plus income tax for Arizona, in one 2026 model: Schedule SE on the profit, then federal and Arizona income tax on what remains after the half-SE deduction — with the quarterly estimate you actually have to send.
W-2 wages use up the Social Security wage base first — a side business alongside a job often owes little or no SS part of SE tax. Profit is after business expenses (Schedule C net), not gross receipts.
Total tax $27,666 — an effective rate of 27.7% on the profit.
| Self-employment tax | $14,130 |
| — Social Security part (12.4%) | $11,451 |
| — Medicare part (2.9%+) | $2,678 |
| Federal income tax | $11,616 |
| Arizona income tax | $1,921 |
| Each quarterly estimate (total ÷ 4) | $6,917 |
Half the SE tax ($7,065) is deducted before the income-tax layers — the model applies it automatically.
SE tax is Social Security (12.4%) plus Medicare (2.9%) on 92.35% of net profit — the 7.65% reduction mirrors the employer share an employee never sees. The Social Security part stops at the $184,500 wage base (counting any W-2 wages first); Medicare never stops, and an extra 0.9% applies above $200,000 ($250,000 MFJ).
Source: IRS Schedule SE (2026); SSA wage base 2026.
Arizona's income tax applies to the profit after the half-SE-tax deduction — $1,921 on the $100,000 default, computed by the same verified engine as the Arizona paycheck calculator (same brackets, deductions and credits). Self-employment does not change the state's brackets; it changes what counts as income before them.
Source: the verified 2026 state engine — Arizona schedule as on the state paycheck pages.
There is no employer withholding a slice of each payment: the total is due in four instalments (Form 1040-ES), and underpaying carries a penalty even if the final return balances. The per-quarter figure above is the total divided by four — the safe-harbour rules (100%/110% of last year) are the alternative and are described in the federal guide.
Source: IRS Form 1040-ES (2026).
Yes — SE tax is entirely federal. What changes by state is the income-tax layer on top, which is why this page exists per state.
Not modelled: the §199A qualified business income deduction depends on business type, W-2 wages paid and property, and phases out above income thresholds. It lowers many real bills below these figures — treat this page as the no-QBI baseline and see a tax professional about eligibility.
Partly: only the salary is payroll-taxed; distributions are not. The LLC vs S-corp calculator in this cluster runs that comparison — with the reasonable-salary caveat front and centre.
Employees split FICA with their employer 7.65%/7.65%. The self-employed pay both halves, but on 100% − 7.65% = 92.35% of profit, so the employer half is not itself taxed.
Arizona Self-Employed Tax Calculator for 2026: on $100,000 of net self-employment profit (single), self-employment tax is $14,130 and Arizona income tax $1,921 — total $27,666, about $6,917 per quarterly estimate.
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The complete self-employment tax model for Arizona in 2026: Schedule SE on the profit, then federal and Arizona income tax after the half-SE deduction, with the quarterly estimate.
On $100,000 single with no W-2 wages: SE tax $14,130, federal income tax $11,616, Arizona tax $1,921 — total $27,666.
SE tax is federal and identical in every state; the state pages exist because the income-tax layer on top is not.
On the default profit the total is 27.7% of profit — the quarterly figure on the page is the amount per 1040-ES instalment.
They reduce the Social Security part: the 12.4% applies only until wages plus SE base reach $184,500 for 2026.
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