First, look to see what method TurboTax is using to calculate your tax. It often doesn't go by the IRS Tax Tables alone. There are alternate calculations it sometimes has to use. For instance, if you have capital gains and/or qualified dividends, it uses the Qualified Dividends and Capital Gain Tax Worksheet. Or do you have Foreign Earned Income--if so, it uses the Foreign Earned Income Tax Worksheet. Did you by any chance have foreign earned income and used the FEI Exclusion? Here's how to see what calculation worksheet(s) TurboTax used to calculate your tax:
If you are using desktop software, open your return and go to Forms Mode. Bring up the Form 1040 Worksheet. Scroll way down and between lines 15 and 16 of the Worksheet is a box called Tax Smart Worksheet. That will show you where the tax calculation came from.
Also print out a copy of your 2022 and 2023 returns and compare them line by line. When you spot a discrepancy that is larger than your expected year-over-year change, examine the details of that item to see if you spot a problem. Look for things like an incorrect entry, transposed figures, commas/decimals in the wrong place, etc.
If after all that, you're still concerned something doesn't gel, you can speak to the folks at TurboTax Support.
TurboTax Support hours are 5AM-9PM Pacific (8AM-12 Midnight Eastern), 7 days/week
FAQ: What is the TurboTax phone number?
https://ttlc.intuit.com/community/using-turbotax/help/what-is-the-turbotax-phone-number/00/25632
