Tax season usually brings a refund check for most workers, but if you're retired, you could wind up owing the IRS.

The IRS uses what's called "provisional income" to determine how much of your Social Security benefits are taxable. Your provisional income is calculated using the following formula: Provisional income = Adjusted gross income (AGI) + tax-exempt interest + 50% of your Social Security benefits

Many retirees are surprised to find that their Social Security benefits may be subject to taxation. Understanding the IRS rules and income thresholds can help you better manage your finances and avoid unexpected tax liabilities.