79 year old working full time - how to figure the effect on tax burden of the earned income. Goal: would less earned income result in less tax burden

Well less income means less tax and less of your Social Security will become taxable.

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

Thank you very much for the reply.   Is there a formula to figure out the amount saved? 

Married filing jointly definitely over the threshold you described.

Are you a professional available to advise with specifics?  I would want to take that off this platform.  

Thank you,

Danelle