The IRS does not care what job the taxes come from -- if it is easier to overwithold from your employee job do it that way -- I did it for years and when I was married I had my husband withhold an extra 100 per month. And if you don't pay quarterly there is a penalty but usually not that much and you have to weigh which way is easiest for you. But your employer can overwithold for you. Also if married have husband do it. All they want is their money. They could care less if Grandma paid it as long as they get paid. Patti