I see no entry for line 20b - taxable social security wages, only gross wages are listed on form. Shouldn't there be a different amount after calculation?

[Hal_Al]

Line 20b of what form?
Line 20b of form 1040 (the main tax form) is for the taxable portion of  Social security benefits.
Social security wages is in box 3 of your W-2 and is not usually reported anywhere on your tax forms

[Critter]

Is your SS benefits listed on 20a ?   If so then none of it must be taxable if nothing is on 20b.

[SteamTrain]

or none of it is taxable..."yet"

keep entering all your income.......brokerage cap gains, dividends, bank interest and even Tax-Exempt income will also end up being used to determine whether line 20b of a form 1040 has any $$ in it.  But it won't be valid until you've entered every scrap.

[VolvoGirl]

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

Make sure you have the right taxable amount showing up for any 1099R you got on lines 15b and 16b.  

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 right side.