How can I correct the tax rate for short term gains? Turbotax is not calculating it correctly, making me overpay. I should fully be in the 24% bracket (married/joint).

[tbyrum-2591]

I had roughly $85,000 in short term gains. Our W2 income is roughly $225,000. I paid estimated taxes to the IRS at 25%. My federal refund goes from receiving $23,000 to owing money after putting in my stocks (with the W2 wages already filled out). This doesn't make sense to me as 24% of $85,000 is roughly $21,000. I should still be in the 24% income bracket when looking at everything.

[VolvoGirl]

Sure anything can happen.  It added to your total income and increased your taxable income.  I once added just $6 of interest and my tax due went up $12! I was right at the line and it pushed me into the next tax bracket.  

When you enter one taxable transaction, you can't just watch the monitor. You increased your overall adjusted gross income and with that come many other changes in your return, not just the incremental tax on the one transaction. More income can make more of any Social Security taxable and can increase or decease any credits you qualified for.

And it increased your AGI and that would decrease some deductions if you itemized on Schedule A. And by increasing your AGI it might reduce some credits you were getting like EIC.   It could be the Medicare Net Investment tax.