It is recommended that the scent ratio for your melt and pour soap is no higher than 3%, which applies to both fragrance oils and essential oils. This means that no more than 3% of the total weight of the soap is made up of these types of oils. To know the final weight of your soap before you start work on the recipe, simply fill one of your mould cells with water and place it onto some kitchen scales. This will give you a rough weight guide, but it is a good idea to add another 10% to the weight, just to be on the safe side.