There is no water added to this recipe nor any preservatives so the shelf like can be calculated as the shelf life of each butter and oil added to the recipe. You will know that it has gone bad when it starts to smell a bit “off”.Use a spoon or spatula to dip rather than your fingers to extend the life of your body butter. To calculate the expiry date you would have to take each ingredient separately to check its expiration, mainly the oils. I have been using infused pine oil with spices which have a shelf life of around one year. The vitamin E added to the recipe will help little bit to extend the shelf life of oils and slow the process of the oils going bad.