Married taxpayers who file a joint return and have taxable income of less than $321,401 may be eligible to deduct 20% of their qualified business income. However, their deduction could be subject to a limitation based on:

Ordinary taxable income (taxable income before any QBI deduction, minus net capital gains and qualified dividends.)

Phase-in rules.

Phaseout rules.

The amount of their taxable income from Form 1040, line 11b.