You may have started DIY your own skincare but mostly following through the recipes listing in drops, cups, teaspoons, etc. I started that way, and I’m also a huge believer in essential oils, so dilution is mostly counted in drops with carrier oils in volume. Measurements in volume tend to be less accurate than in weight, due to the specific gravity of each ingredient is not taken into account. This is why it is always best to formulate in percentage and work out the weight-based formula of the batch size of your natural cosmetics.