My wife teaches piano lessons. In the past, this income always qualified for the QBID (using TT desktop). This year, using TT online, the QBID is shown as 0. Why?

[crossmusic]

Nothing about this business changed during 2025 from previous years. This is a sole proprietorship.

[MaxA1]

There may be a variety of reasons why the QBID is no longer populating.  Did you have any business losses in the previous year(s) that may cause a QBI Loss carryover that is offsetting any income being used for the QBID calculation? Are there any current-year business losses that are offsetting this business income, thus wiping out the QBID?

Another possibility is that your taxable income before QBID, minus any capital gains during the year is zero, which will ‌result in zero QBID for the year.  To test this out, try increasing your Income from the Piano Lessons in TurboTax and review your tax return summary to see if QBID gets applied.  If you now show the QBID, then you found your answer.  Form 8995 shows how the QBID is calculated.