This depends on whether you are simply doing a small section of your hair or the entire head. If you're just doing a small section, check out our new Mini Lightening Kit! An entire head could require between 2-5 Lightening Kits. Just remember, it’s always better to be safe than sorry and have extra on hand just in case. We suggest mixing one bottle and one packet at a time,  that way if you don’t need the others you can save them for next time! Our lightening kits are good for over a year!