Interactive label guide
CBD strength calculator
Turn the numbers on an oil label into concentration and comparable unit cost. This tool explains a product; it does not choose a dose or recommend CBD for a symptom.
Label calculator
Enter the bottle facts
Use total CBD for the entire container—not a per-serving figure. Price is optional.
Calculated label facts
- Concentration
- 33 mg/ml
- Approx. percentage
- 3.3%
- Cost per 100mg
- £3.30
- Cost per ml
- £1.10
Percentage is a label-comparison conversion: 10mg/ml ≈ 1%. Confirm the manufacturer's label and lab report.
What “strength” actually means
A bottle can show a large total CBD number simply because it contains more liquid. Concentration answers the more useful question: how many milligrams are present in each millilitre? Divide total CBD in milligrams by bottle volume in millilitres. A 1000mg, 30ml oil is about 33.3mg/ml; a 1000mg, 10ml oil is 100mg/ml. The totals match, but the concentrations do not.
Percentage is another way of expressing roughly the same relationship for oil labels. In the common weight-per-volume convention, 1% corresponds to about 10mg/ml. Percentage is useful for comparison, but the manufacturer's current packaging and certificate should remain the source of truth.
How to use the results
- Compare products using the same unit, preferably mg/ml.
- Check whether the milligrams refer to the whole bottle or one serving.
- Use cost per 100mg to compare value without allowing bottle size to distort it.
- Keep spectrum, ingredients, flavour, lab documentation and expiry in the comparison.
- Recheck the retailer page because prices and variants change.
A lower cost per 100mg is not automatically a better purchase. It says nothing about whether the strength, flavour, format or ingredients suit the intended comparison. This is why thCBDx scores value as one dimension rather than ordering every product solely by its biggest milligram number.
What this calculator deliberately does not do
It does not convert a symptom into a product, predict an effect, calculate drops to take or replace the product label. Drop size varies between droppers, and a retailer's “per drop” or “per pipette” figure is not personalised advice. The calculator also does not assess whether a product is lawfully marketed or on the FSA public list.
The Food Standards Agency currently advises healthy adults to limit CBD from food to 10mg a day in total. It advises against CBD consumption for children, people taking medication, those trying to conceive, pregnant or breastfeeding people and people who are immunosuppressed. Anyone with health concerns should speak to a healthcare professional. This precautionary guidance concerns CBD foods and supplements; it is not a recommendation to start using CBD.
Worked label examples
500mg in 30ml: 500 ÷ 30 = 16.7mg/ml, or approximately 1.7%. 2000mg in 10ml: 2000 ÷ 10 = 200mg/ml, or approximately 20%. The second bottle has four times the total CBD but around twelve times the concentration because its volume is one third as large.
If those bottles cost £16.99 and £35.75, respectively, their rough costs are £3.40 and £1.79 per 100mg. That numerical advantage does not tell a buyer which concentration is suitable; it only makes the price relationship visible.
Continue comparing
Read our CBD label guide, use the oil comparison table, or see how thCBDx scores products. Source: Food Standards Agency CBD guidance, checked 3 August 2026.