Buying guide
CBD Oil Strengths Compared: 500mg vs 1000mg vs 1500mg vs 3000mg
The number on a CBD oil bottle is the total in the whole bottle, not a serving. Here is how to compare 500mg, 1000mg, 1500mg and 3000mg oils by concentration and price per milligram.
The number on a CBD oil bottle is the total amount of CBD in the whole bottle, not the amount in a drop. To compare 500mg, 1000mg, 1500mg and 3000mg oils fairly you need two more figures: the bottle size and the concentration. Once you do the sums the range makes sense. Our 500mg and 1500mg oils, for example, are the same concentration, 5%, in different bottle sizes.
Key takeaways
- Total mg divided by bottle size in ml gives mg per ml. Divide that by 10 and you have the percentage: 50mg per ml is a 5% oil.
- Calm Leaf's 500mg (10ml) and 1500mg (30ml) oils are both 5%. The 1000mg is 3.3% and the 3000mg is 10%.
- Bigger bottles cost less per milligram: from 4.0p a mg for the 500mg to 2.7p a mg for the 3000mg at today's prices.
- A stronger oil is not a better oil. It is a more concentrated one. How much you take is a separate choice, and the only official UK figure is the FSA's 10mg a day across all CBD foods.
How to read the numbers on a bottle
Four figures describe any CBD oil, and a good label gives you all of them:
- Total CBD is the headline number, such as 1500mg. It is the amount in the whole bottle.
- Bottle size is the volume in millilitres, usually 10ml or 30ml.
- Concentration is the share of the oil that is CBD, shown as a percentage. It is the total divided by the volume: 1500mg in 30ml is 50mg per ml, which is 5%.
- CBD per drop is the concentration divided by the number of drops in a millilitre. Droppers differ, and about 20 drops to the millilitre is a common figure. Use the per-drop figure printed on the product page or label where there is one.
The first figure tells you how much CBD you are buying. The concentration tells you how strong each drop is. They are not the same thing, which is why a 1500mg bottle is not automatically three times as strong as a 500mg one.
The four Calm Leaf oils side by side
| Oil | Bottle | Concentration | CBD per ml | Price | Price per mg |
|---|---|---|---|---|---|
| CBD Oil 500mg | 10ml | 5% | 50mg | £19.99 | 4.0p |
| CBD Oil 1000mg | 30ml | 3.3% | 33mg | £29.99 | 3.0p |
| CBD Oil 1500mg | 30ml | 5% | 50mg | £49.99 | 3.3p |
| CBD Oil 3000mg | 30ml | 10% | 100mg | £79.99 | 2.7p |
Prices correct on 29 October 2026 and may change. The 3000mg oil is currently reduced from £89.99; at the list price it works out at 3.0p per mg. Each product page lists an approximate CBD per drop.
What actually changes as you go up
500mg and 1500mg: same concentration, different size
Both are 5% oils, so every millilitre holds the same 50mg of CBD. The difference is volume. The 1500mg is a 30ml bottle with three times the CBD for two and a half times the price, which makes it about 17% cheaper per milligram. The 500mg is a 10ml bottle at £19.99, the smallest outlay in the range and a sensible size if you want to try an oil before committing to a larger one.
1000mg: the lowest concentration in a 30ml bottle
At 3.3% the 1000mg oil is the least concentrated of the three 30ml bottles. Each drop holds the least CBD, about 1.7mg according to its product page, so the steps between one serving and the next are the smallest in the range. It also works out cheaper per milligram than the 1500mg.
3000mg: the highest concentration and the lowest price per mg
At 10% the 3000mg oil is twice as concentrated as the 1500mg, at around 5mg a drop on its product page. That means fewer drops reach any given amount, and the price per milligram is the lowest in the range. It also means a very small change in the number of drops makes a large change in the amount, so read the FSA's 10mg a day advice before you choose it. Two drops of this oil already reach 10mg.
Does a stronger bottle mean you take more?
Not by itself. Concentration changes how many drops it takes to reach a given amount. It does not change the amount that is appropriate for you. The only official UK figure is the FSA's advice that healthy adults should not consume more than 10mg of CBD a day from food, and that is a total across every CBD product you take. Our guide to how much CBD to take in the UK explains the advice and shows the label maths for each format.
Which bottle suits which shopper
| If you want… | Look at | Why |
|---|---|---|
| The smallest outlay and a bottle you will get through quickly | 500mg (10ml) | £19.99, 5% concentration |
| The smallest step between one drop and the next | 1000mg (30ml) | 3.3%, the lowest concentration in a 30ml bottle |
| A 5% oil in a larger bottle at a lower price per mg | 1500mg (30ml) | 3.3p per mg against 4.0p for the 500mg |
| The highest concentration and the lowest price per mg | 3000mg (30ml) | 10%, 2.7p per mg, and you need to be comfortable counting drops |
Prefer a counted piece to a dropper? Compare oil with capsules and gummies in our guide to CBD oil vs CBD gummies.
How to compare any CBD oil
The same sums work on any brand. Say another oil is 1000mg in 10ml for £34.99. That is 1000 ÷ 10 = 100mg per ml, a 10% oil, at 3.5p per mg. Put that next to a 30ml bottle at 3.3% and you can see straight away that the two are not comparable by the headline number alone. Always compare concentration and price per milligram, not the figure on the front.
Checks that matter at any strength
- A lab report for your batch. Every Calm Leaf batch is independently tested, and you can request the certificate that matches the code on your bottle. Our guide to lab testing and COAs shows how to read one.
- A named carrier oil and a full ingredient list on the label.
- A best-before date. A bigger bottle only makes sense if you will use it in time.
- THC testing. Our UK CBD law guide explains the rules.
For the full buying checklist, read our 2026 CBD oil buying guide. Browse the whole range in the Calm Leaf oils collection, with free UK delivery on orders over £49.
Frequently asked questions
What does 5% CBD oil mean?
It means 5% of the oil is CBD, which is 50mg of CBD in every millilitre. A 10ml bottle at 5% holds 500mg in total, and a 30ml bottle at 5% holds 1500mg.
How many drops are in a 30ml bottle of CBD oil?
Dropper sizes vary, but around 20 drops to the millilitre is a common figure, which gives roughly 600 drops in a 30ml bottle. The per-drop figures on the Calm Leaf 1000mg, 1500mg and 3000mg product pages are consistent with that.
Is 3000mg CBD oil better than 500mg?
It is more concentrated, at 10% against 5%, and costs less per milligram, but it is not better in any other sense. The right bottle depends on size, budget and how you prefer to count servings. The amount you take is a separate choice.
Which Calm Leaf oil is the best value per milligram?
At prices on 29 October 2026, the 3000mg oil is lowest at 2.7p per mg, then the 1000mg at 3.0p, the 1500mg at 3.3p and the 500mg at 4.0p.
Do I need a different lab report for each strength?
Yes. Each batch of each product should have its own certificate of analysis. Match the batch code on your bottle to the code on the report.
Can I use CBD oil alongside capsules or gummies?
The FSA's advice of no more than 10mg of CBD a day for healthy adults is a total across all CBD foods, so you need to add up everything you take.
Related Calm Leaf guides
- How Much CBD Should I Take? The UK FSA 10mg Guidance Explained
- CBD Lab Testing and COAs Explained
- How to Choose the Best CBD Oil in the UK: A 2026 Buying Guide
- CBD Oil vs CBD Gummies: Which Format Suits Your Routine?
Sources
Last reviewed: 29 October 2026. General information only, not medical advice. Calm Leaf CBD food supplements and cosmetics are not medicines and are not intended to diagnose, treat, cure or prevent any disease. For adults aged 18 and over.
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