why is $450 of my social security benefits taxable?

The part of your Social Security benefits that you pay taxes on is based on your provisional income. This is your adjusted gross income (AGI) plus half of your Social Security benefits. If your provisional income exceeds certain thresholds, a portion of your benefits becomes taxable.

1. Calculate your provisional income: Add half of your Social Security benefits to your other income (wages, pensions, interest, dividends, etc.).
2. Compare to the thresholds:
   • If you're single and your provisional income exceeds $25,000, part of your benefits may be taxable.
   • If you're married filing jointly and your provisional income exceeds $32,000, part of your benefits may be taxable.

For more details, you can refer to the IRS guidelines:

• IRS Social Security Income FAQ
• IRS reminder on taxable Social Security benefits