401ks are pretax money. In general, people put ~5% of their (pretax) money into 401ks because, on average, companies will match that ~5%, effectively doubling

401ks are pretax money. In general, people put ~5% of their (pretax) money into 401ks because, on average, companies will match that ~5%, effectively doubling your retirement savings instantly. A common thing to utilize after that is a ROTH IRA, which is paid with after tax money, but the money grows tax free. The max ROTH IRA contribution per year is $6k, $12k if you're married.