What determines how much of our Social Security is subject to being taxed?

[ernjo]

TurboTax has calculated that 59.85% of my Social Security is taxable. I know that up to 85% can be taxed however I would like to know how that percentage is calculated.

[MinhT]

The percentage of your Social security benefits to be included in your taxable income results from a complex formula.

This formula takes into account your filing status, the amount of your SS benefits and the amounts and natures of your other income. TurboTax will calculate this percentage automatically for you.

If you wish to make simulations, you can visit this website:

https://www.calcxml.com/calculators/how-much-of-my-social-security-benefit-may-be-taxed?skn=#results