Where can I see taxable social security calculations?

It's one of the worksheets.  See:

How to print worksheets for 2020 taxes? (intuit.com)

To see the Social Security Benefits Calculation Worksheet  in Turbo Tax Online version you would have to save your return with all the worksheets to your computer.   Or if you are using the Desktop CD/Download Software you can switch to Forms Mode (click Forms in the upper right) and click on SS in the list on the left side.

Is your Social Security taxable?

https://ttlc.intuit.com/community/income/help/is-my-social-security-income-taxable/00/25600

Before filing,  You can preview the 1040 or print the whole return

https://ttlc.intuit.com/community/accessing/help/how-do-i-preview-my-turbotax-online-return-before-filing/00/26160

Up to 85% of Social Security becomes taxable when all your other income plus 1/2 your social security, reaches:

Married Filing Jointly: $32,000

Single or head of household: $25,000

Married Filing Separately: 0