Social security benefits are taxed based on the overall income on the tax return. Confirm that you entered the Forms SSA-1099 correctly for each of you on your return. A brief explanation of how it is calculated is provided below.
The social security benefits are entered, then half of the benefits are added to your other taxable income, such as your pension (and some exempt income if applicable) to determine if any amount of the social security is taxable. If half of your benefits combined with your other taxable income is greater than the first threshold of $25,000 for single ($32,000 for married filing joint), then some of your social security benefits will be taxed. The amount of that combined total determine exactly how much of it is taxed, but never more than 85%. There is a second threshold of #34,000 for single ($,44,000 for married filing jointly) which, when reached the full 85% of social security benefits will be included on the tax return.
TurboTax will do all the calculations and determine if any of your benefits are taxable. The TurboTax article below may be helpful as well.
https://ttlc.intuit.com/replies/3299920
