How the maths works
Divide the total CBD in the bottle by the bottle size to get the strength in mg per mL. Then divide your dose in mg by that strength to get the volume in mL.
For example, a 30 mL bottle containing 3,000 mg of CBD is 100 mg per mL. A 25 mg dose is 25 รท 100 = 0.25 mL.
Use the syringe, not drops
Drop size varies with the dropper, the oil and the temperature, so counting drops is not accurate. Prescription oils in Australia come with, or can be dispensed with, an oral syringe marked in millilitres. Use that, and ask your pharmacist to show you if you are unsure.
This calculator does arithmetic only. It does not tell you what dose to take. Your dose is set by your prescriber. If the result does not match the label on your medicine, follow the label and check with your pharmacist.