How this number is made
The qualified business income deduction is often described as 20% of that income. The real deduction is limited by taxable income, by whether the business is a specified service, and by W-2 wages and property. This page is only the 20% before those limits, so you can see the ceiling, not the deduction you will get.
- Qualified business income is not always the same as net profit. Capital gains are generally excluded.
- If your taxable income is high, do not treat this number as yours.
Formula
Ceiling = qualified business income × 20%.
Worked example
With the figures already in the form, 20% before the statutory limits is $16,000.
Questions
Why not compute the real limit?
The wage and property limit and the specified-service phaseout need facts this form does not have. Publishing a fake precise deduction would be worse than showing the simple 20%.
Does it reduce self-employment tax?
No. It is an income-tax deduction. Self-employment tax is computed without it.