Are Social Security benefits taxable?

Sometimes. Whether your Social Security benefits are taxed depends on your total income - specifically a measure that combines your other income with part of your benefits. If that total is low, your benefits may not be taxed at all; above certain thresholds, up to 50% and then up to 85% of benefits can become taxable. These thresholds are set by law and are not indexed for inflation. Some states tax benefits too. Because the calculation is easy to get wrong, tax software or a professional can help you figure the taxable portion.