How much do you shorten your life if you donate one of your kidneys?

Donate! Not one single day! it is very safe and experience in people who are born with one kidney, soldiers who lost a kidney from gunshot wounds in wwi and wwii and experience with donors since the 1960's show the life expectancy is unequivocally normal. But what does change is a big change in your ethical and moral standing. You have given the "gift of life".