How to Compare CBD Oil Strengths on UK Labels in 2026: A Practical Percentage and Milligram Guide
Photo: elsaolofsson, CC BY 2.0, via Wikimedia Commons
UK shoppers now see a wide range of CBD oil strengths, from modest 5% bottles to 20% products and beyond. The percentage on the front of the label is useful, but it is not enough on its own. A clear comparison depends on the bottle size, the total amount of CBD stated, the concentration per millilitre and the way a serving is measured. At CBD Oil Ltd, we prefer a ladder approach: understand each rung, compare like with like, and move only when the reason is clear.
Why the percentage is only the first rung
A CBD oil percentage describes the concentration of CBD within the total volume of oil. In typical UK labelling, a 10ml bottle at 5% contains around 500mg of CBD in total. The same 5% strength in a 30ml bottle contains around 1,500mg in total, but the concentration per millilitre remains the same. This is the first common source of confusion: a larger bottle can contain more CBD overall while not being stronger drop for drop.
The more useful figure is milligrams per millilitre, usually written as mg/ml. For typical oil products, a simple rule of thumb is that a 1% concentration is approximately 10mg/ml. That makes 5% roughly 50mg/ml, 10% roughly 100mg/ml, 15% roughly 150mg/ml and 20% roughly 200mg/ml. Always check the label arithmetic rather than relying on the rule alone, because packaging should state total CBD content and bottle volume clearly.
| Strength | Typical total CBD in a 10ml bottle | Approximate mg per ml | Approximate mg per drop at 20 drops per ml |
|---|---|---|---|
| 5% | 500mg | 50mg/ml | 2.5mg |
| 10% | 1,000mg | 100mg/ml | 5mg |
| 15% | 1,500mg | 150mg/ml | 7.5mg |
| 20% | 2,000mg | 200mg/ml | 10mg |
The drop figure is an estimate. Dropper markings and drop sizes vary, so the label and the supplied dropper should always take priority.
Drops, servings and the arithmetic that matters
A serving is not a standardised measure across every product. Some shoppers use a few drops; others use a marked dropper measure such as 0.25ml or 0.5ml. The concentration only becomes meaningful when it is linked to the amount actually measured.
Consider a worked example. Product A is a 10ml bottle at 10%, containing around 1,000mg in total and approximately 100mg/ml. Product B is a 30ml bottle at 5%, containing around 1,500mg in total and approximately 50mg/ml. Product B has more CBD in the bottle overall, but Product A is twice as concentrated per millilitre. If someone measures 0.5ml from each, Product A provides around 50mg and Product B provides around 25mg. The larger bottle is not the stronger bottle in this comparison.
A second example is useful when moving from 5% to 10%. A 10ml 5% bottle at roughly 50mg/ml gives about 12.5mg in a 0.25ml measure. A 10ml 10% bottle at roughly 100mg/ml gives about 25mg in the same measure. The percentage has doubled, and so has the amount in that measured serving. That is why comparing the percentage alone, without the bottle size and serving measurement, can lead to a false sense of what has changed.
A measured framework for the strength ladder
A sensible comparison framework does not need to be complicated. It should, however, be consistent.
- Confirm the label figures. Check the total CBD content, bottle volume and stated mg/ml. A label that gives only a percentage is less easy to verify than one that gives both percentage and milligrams.
- Start with the lowest practical concentration. If a lower strength allows a comfortable, measurable serving, there is no automatic reason to begin higher. The ladder is a comparison tool, not a target to climb.
- Measure consistently. Use the same dropper and the same measure each time. Record whether the serving is expressed in drops or millilitres.
- Keep a simple log. Note the product, batch, amount measured and time of day. This is a record-keeping exercise, not a substitute for professional advice.
- Review before changing. If the routine is stable and the measurement is clear, a change can be considered on its merits. Moving up simply because a higher percentage exists is not a sound buying reason.
Questions to ask before choosing a stronger bottle
Before moving from 5% to 10%, or from 10% to 20%, ask whether the comparison is genuinely like for like. Is the bottle size the same? Is the carrier oil the same? Is the flavouring the same? Does the new bottle use the same dropper design? Can a smaller serving be measured accurately from the stronger product?
It is also worth asking whether the product information is clear enough to verify. Does the supplier publish batch details or a certificate of analysis? Are storage instructions present? Is the total CBD content stated in milligrams as well as percentage? These questions support quality and compliance, and they help shoppers avoid buying on the strength of a large number alone.
Finally, consider whether a stronger bottle is being chosen to solve a measurement problem. If the issue is an unclear dropper, an inconsistent routine or confusion over mg/ml, a higher percentage may add cost without adding clarity. A better solution may be a product with clearer labelling and a more practical measure.
The ladder is a comparison tool, not a destination
There is no requirement to progress from 5% to 20%. Many households will find that a lower or mid-range concentration suits their preferred measuring routine. Others may prefer a stronger concentration because it allows a smaller volume to be measured. The important point is that the choice should be based on verifiable label information, consistent measurement and a clear reason.
At CBD Oil Ltd, our view is straightforward: a strength ladder is most useful when it replaces guesswork with arithmetic. Read the bottle, compare the milligrams, check the serving size and keep the routine steady. That approach is more reliable than chasing a percentage.
