With a known concentration level of any medicine, any amount of THC or CBD can be administered. The volume of medicine required to achieve any specific THC or CBD dose is calculated by this formula: Target Dose (mg) / Concentration (mg/mL) = Volume of Dose (mL)
For example, if you have a 200mg THC target dose with a 30mg/mL THC oil, the calculation is 200 / 30 = 6.67mL. Droppers are graduated at .25mL, .5mL, .75mL, and 1mL, so this could be administered by taking 6 back-to-back 1mL doses following by a dose between the .5mL and .75mL line. For maximum precision, you can take a specific number of drops to make up for any dose that’s not in .25mL increments, using the fact that there are 30 drops in 1mL. So in this case, 6.5mL could be taken, leaving .17mL remaining. .17mL x 30drops/mL = 5.1 drops, so taking 6.5mL + 5 drops in this example would provide 200mg THC.
The same calculation can be done with extract. Extract is often reported in percentage and it is important to convert that to mg/g for calculation purposes (ex. a 60% THC oil is 600mg/g THC). For example, if you have a 200mg THC target dose with a 600mg/g THC extract, the calculation is 200/600 = .33g. This can be measured precisely by weighing the extract on rice paper or a small piece of food on a .001g scale (extract can’t be applied directly to scale surface). Doses can also be estimated from the .1g graduated lines on the syringe. Therefore, a .33g dose could be estimated by squeezing out about three graduations of the syringe. Many patients start with or switch over to estimating doses due to the hassle of weighing each dose, but starting with a scale can be a great way for new patients to get exact dosing and understand the size/weight relationship of the extract to help with estimating.