How the calculator works

2026 figures used

Item	Single	Married joint	Head of household
Standard deduction	$16,100	$32,200	$24,150
10% bracket up to	$12,400	$24,800	$17,700
12% up to	$50,400	$100,800	$67,450
22% up to	$105,700	$211,400	$105,700
24% up to	$201,775	$403,550	$201,750
32% up to	$256,225	$512,450	$256,200
35% up to	$640,600	$768,700	$640,600
QBI deduction limit starts	$201,750	$403,500	$201,750

Above the last bracket the rate is 37%. Source: IRS Rev. Proc. 2025-32.

Self-employment tax

Net profit is multiplied by 92.35%. Social Security tax of 12.4% applies up to the $184,500 wage base for 2026, reduced by any W-2 wages that already count toward it. Medicare tax of 2.9% applies to all of it. Additional Medicare Tax of 0.9% applies to combined earnings above $200,000 ($250,000 married filing jointly). Profit under $400 of net earnings carries no self-employment tax.

Safe harbor

The minimum payment shown is the smaller of 90% of this year's tax and, if you enter it, 100% of last year's total tax (110% when last year's adjusted gross income was above $150,000). It is net of tax already withheld.

What it does not do

• Credits such as the child tax credit and education credits.
• Itemized deductions, retirement contributions, self-employed health insurance, home office.
• Capital gains, net investment income tax, alternative minimum tax.
• Credits against the annualized method are not modeled, and the Form 2210 for 2026 has not been released, so the "In lumps or seasons" mode follows the 2025 form and must be rechecked.
• State and local tax beyond a flat rough rate you enter.

Sources

• IRS Rev. Proc. 2025-32
• IRS: Estimated taxes
• IRS: Self-employment tax
• SSA: Contribution and benefit base

Last checked October 11, 2026.