Security is only designed to replace 40% of your income. According to the Social Security Administration, just $4 out of every $10 of the average American worker’s pre-retirement salary will be replaced by Social Security retirement benefits. Since the Social Security formula is rather top-heavy, this percentage can be expected to be even lower for higher-income workers. Experts generally suggest that it takes about 80% of your pre-retirement income to sustain your lifestyle, so the rest needs to come from other sources.