married taxpayers who file a joint returnand 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: calculate the QBI deduction for ned who is filing single. his taxable income before any QBI deduction is $160,6000. he is not engaged in an sstb. his QBI is $60,000. he did not have any capital gains. he had $15,000 of qualified wages and $35,000 of qualifying property.