the worksheet is on page 26 of this
http://www.irs.gov/pub/irs-pdf/i1040.pdf

page 6 of this explains the 50%-85% taxable

http://www.irs.gov/pub/irs-pdf/p915.pdf


if you file a joint return and one half of your social security benefits plus other income is over 32,000 then 50% of social security benefits are taxable.

If you add one half of your social seucirty benefits plus your other income and iit is over $44,000 then 85% of social security benefits are taxable.

Those numbers have not changed for many years now. no adjustment for inflation. toal BS.