CBD Dosage Calculator
Turn the CBD dose you or your doctor chose into mL, drops or gummies for your exact product, plus strength, cost per dose and an edibles mixing helper.
This calculator does label math, nothing more. You tell it the dose in milligrams (mg) that you or your doctor chose, plus your product’s strength. It tells you how much of that product equals that dose. It does not recommend a dose for any condition, age or body weight.
- There is no standard CBD dose for over-the-counter products. Choose a dose with a doctor or pharmacist.
- Labels list strength in different ways: total mg per bottle, mg per mL or mg per serving. The calculator turns these into the same unit.
- Labels can be wrong. Check the product’s lab report (COA) before you rely on the numbers.
- CBD can interact with medicines, may cause drowsiness and is not advised during pregnancy or breastfeeding.
How to use this calculator
- Enter your dose in mg. Use the amount you and your doctor or pharmacist agreed on.
- Enter your product’s strength. For an oil or tincture, enter the total CBD in the bottle (mg) and the bottle size (mL). For gummies or capsules, enter the mg of CBD in each piece.
- Read the results. You’ll see how many mL, drops or gummies match your dose. You’ll also see the mg per mL, mg per serving and, if you enter the price, the cost per mg.
- Making edibles at home? Use the mixing helper. Enter the total mg of CBD you add to a recipe and the number of pieces you cut. It shows the mg per piece.
Example: a 30 mL bottle that contains 600 mg of CBD has 20 mg per mL (600 ÷ 30). If your chosen dose is 10 mg, that is 0.5 mL. If the bottle cost $45, the cost is $0.075 per mg (45 ÷ 600). These numbers only show the math. They are not a suggested dose.
Homemade edibles may not mix evenly, so the real amount in each piece can differ from the average the mixing helper shows.
Why there’s no standard CBD dose
The FDA has approved only one CBD product: Epidiolex, a prescription drug. It is approved to treat seizures linked to three rare conditions: Lennox-Gastaut syndrome, Dravet syndrome and tuberous sclerosis complex, in patients 1 year and older.
Epidiolex is dosed by body weight, in milligrams per kilogram, and is started and adjusted by a prescriber. Its label also calls for liver blood tests. That dosing is for a specific prescription medicine and specific conditions. It is not a guide for over-the-counter CBD oils, gummies or other products.
Over-the-counter CBD products are not FDA-approved. The FDA says some are marketed with unproven medical claims and are of unknown quality. Without approval and good-quality trials for these products, there is no tested, standard dose to point to.
“Start low, go slow”
You may hear the phrase “start low, go slow”. The Arthritis Foundation uses it in its CBD guidance for adults with arthritis. The idea is to begin with a low dose and increase in small steps over time if needed, while keeping notes on how you feel. The Foundation also says people should talk to the health care provider who treats them before trying CBD.
We share this as general background, not a plan. Your doctor or pharmacist can help you decide whether CBD makes sense for you and how to approach it.
How to read the strength on a label
| What the label says | What it means | Example |
|---|---|---|
| Total mg per bottle | All the CBD in the whole bottle | “1000 mg CBD” on a 30 mL bottle |
| mg per mL | CBD in each milliliter of liquid | 1000 mg ÷ 30 mL = about 33 mg per mL |
| mg per serving | CBD in the serving size the brand chose | “25 mg per serving (1 gummy)” |
The big number on the front of a bottle is usually the total for the whole bottle, not per serving. Two bottles with the same total mg can have very different strengths if they are different sizes.
Droppers are not standardized. A “full dropper” from one brand may not hold the same amount as another, and the number of drops in 1 mL depends on the dropper and the oil. If you need accuracy, use a dropper or oral syringe marked in mL. Treat the calculator’s drop count as an estimate.
Check the COA
A certificate of analysis (COA) is a lab report for a product batch. Studies show labels are not always accurate. In one study of 84 CBD products sold online, only about 31% had a CBD amount close to the label. THC was found in 18 of them. The Arthritis Foundation advises buying from companies that test each batch and provide a COA from an independent lab.
When you look at a COA, check:
- Batch match: the batch or lot number on the COA matches the one on your product.
- CBD amount: the CBD the lab measured is close to what the label claims.
- THC: how much THC the lab found, especially if you are drug tested.
- Who tested it: an independent lab, not the brand itself.
If the lab result and the label differ, use the lab number in the calculator.
Safety
Talk to a doctor or pharmacist before using CBD if you take any medicine. The FDA says CBD can affect how other drugs work, potentially causing serious side effects, and that CBD can cause liver injury.
- Drug interactions: a published case report described a man taking the blood thinner warfarin whose blood-clotting test (INR) rose after he started CBD, and his warfarin dose had to be lowered. The Arthritis Foundation also lists warfarin, corticosteroids, tramadol, certain antidepressants and some over-the-counter pain relievers among drugs that may interact with CBD. The Epidiolex label lists interactions with seizure medicines such as clobazam and valproate.
- Pregnancy and breastfeeding: the FDA strongly advises against using CBD in any form while pregnant or breastfeeding.
- Drowsiness: the FDA lists drowsiness as a possible effect. Using CBD with alcohol or other sedating drugs raises that risk.
- Driving: the Epidiolex label advises patients not to drive or operate machinery until they know how it affects them. That is sensible caution with any CBD product.
- Male fertility: the FDA notes that animal studies found harm to male reproductive health. More research is needed in people.
Drug tests
Drug tests look for THC, not CBD. In a lab study, single doses of pure CBD did not produce a positive urine drug test under federal workplace cutoffs. But the same researchers found that CBD products that also contain THC may cause a positive result. Full-spectrum products can contain THC, and labels may not always be accurate. If you are drug tested, check the COA for THC and consider the risk carefully.
CBD for pets
The FDA has not approved CBD for any use in animals. Don’t use this calculator to work out a dose for a pet. The FDA recommends that pet owners talk with their veterinarian about treatment options.
Frequently asked questions
How much CBD should I take?
We can’t tell you, and no calculator can. Over-the-counter CBD has no FDA-approved dose. Decide on a dose with your doctor or pharmacist, then use this calculator to measure it from your product.
How many drops are in 1 mL?
It varies by dropper and by oil, so there is no single answer. For accuracy, measure in mL with a marked dropper or oral syringe rather than counting drops.
Why doesn’t my result match the serving size on the label?
The serving size is the amount the brand chose. Your result is based on the dose you entered. If they differ, the calculator shows how much product matches your dose, not the brand’s serving.
Can I use the Epidiolex dose for a store-bought CBD oil?
No. Epidiolex is a prescription drug for specific seizure conditions, dosed by weight under medical supervision. Its dosing is not a guide for over-the-counter products.
Can I use this calculator for my dog or cat?
Please don’t. The FDA has not approved CBD for any use in animals. Ask your veterinarian.
These statements have not been evaluated by the Food and Drug Administration. CBD products are not intended to diagnose, treat, cure or prevent any disease. See our CBD & Medical Disclaimer.
Sources
- FDA: What You Need to Know (And What We’re Working to Find Out) About Products Containing Cannabis or Cannabis-derived Compounds, Including CBD
- FDA: Regulation of Cannabis and Cannabis-Derived Products, Including Cannabidiol (CBD)
- FDA: What You Should Know About Using Cannabis, Including CBD, When Pregnant or Breastfeeding
- DailyMed (NIH): Epidiolex (cannabidiol) prescribing information
- NCCIH: Cannabis (Marijuana) and Cannabinoids: What You Need To Know
- Bonn-Miller MO, et al. Labeling Accuracy of Cannabidiol Extracts Sold Online. JAMA. 2017
- Grayson L, et al. An interaction between warfarin and cannabidiol, a case report. Epilepsy & Behavior Case Reports. 2017
- Spindle TR, et al. Urinary Pharmacokinetic Profile of Cannabinoids Following Administration of Vaporized and Oral Cannabidiol and Vaporized CBD-Dominant Cannabis. J Anal Toxicol. 2020
- Arthritis Foundation: CBD for Arthritis Pain: What You Should Know