Question: how many drops of essential oil in 5ml of carrier oil?
Answer: The best rule of thumb is one drop of essential oil per teaspoon of carrier oil for a 1% dilution. For a 0.50% dilution you can't exact measure half a drop, so instead you will increase the amount of carrier oil. Of course when I say “carrier oil” I mean any carrier, including a lotion, or even aloe vera.