CBD Guides

CBD oil strengths explained: convert % to mg per drop (UK)

By the Honest CBD Co team · 6th September 2026 · Updated 1st October 2026

Pick a bottle that lets you measure a small, precise dose, then follow the “start low and go slow” rule that runs right through the clinical dosing literature. For most people that means starting around 10 to 20mg a day, holding steady for a fair trial, then adjusting a drop at a time. Our 10% oil works out at about 5mg a drop, which is exactly this kind of measured start. If you want the maths behind converting a percentage on a label into milligrams on your tongue, the calculation section below walks through it drop by drop.

TL;DR:

Mg per ml is the number that determines your dose: total mg divided by bottle volume. A 10ml bottle of 10% oil holds 1,000mg, which is 100mg per ml.

A drop is roughly 0.05ml, so a 10% oil gives about 5mg per drop and a 20% oil about 10mg per drop. Two drops of 10% is a tidy 10mg dose.

Start around 10 to 20mg a day, give it a fair trial at the same time each day, and adjust by a drop at a time rather than jumping strengths.

Capsules remove the counting entirely: a fixed dose per capsule, in 40mg, 80mg and 120mg strengths.

Pick a strength where your daily dose is a small, countable number of drops. Concentrated syringe formats (50% and 85%) suit experienced users who measure by volume.

What does CBD oil strength actually mean?
Which CBD strength band suits you: low, medium or high?
How do you calculate your CBD dose from the label?
How should you titrate up from your starting dose?
What does the FSA say about safe CBD intake, and what should you watch for?
Which bottle strength should you actually buy?
What we see most often when people get their CBD dose wrong
Find the right strength in the Honest CBD Co range
Sources

What does CBD oil strength actually mean?

Strength on a CBD label usually shows up in three different ways, and mixing them up is the single biggest reason people buy the wrong bottle. Total mg is the amount of CBD in the whole bottle. Percentage (%) is that total expressed as a proportion of the bottle’s contents, so 10% means roughly 100mg of CBD in every millilitre. Mg per ml is the figure that actually determines your dose, because it tells you how much CBD sits in each millilitre of liquid you squeeze out.

Here’s the conversion that ties them together:

Total mg ÷ bottle volume (ml) = mg per ml

Take our 10% Full Spectrum Oil: 1,000mg of CBD in a 10ml bottle. That’s 1,000 ÷ 10, which comes to 100mg per ml. A standard dropper holds around 1ml, and a drop is roughly 0.05ml, so a full dropper gives you about 20 drops and each drop of a 10% oil delivers about 5mg. (Some droppers give smaller drops, closer to 25 or 30 per ml, so it’s worth counting yours out once.)

A quick reference makes this clearer, using a drop of about 0.05ml:

Bottle	Total CBD	Approx. mg per ml	Approx. mg per drop
30ml (1%)	300mg	10mg/ml	0.5mg
10ml (5%)	500mg	50mg/ml	2.5mg
10ml (10%)	1,000mg	100mg/ml	5mg
10ml (20%)	2,000mg	200mg/ml	10mg

A few points worth holding onto when you’re reading a label:

The bottle’s total mg tells you almost nothing about your dose until you divide it by the volume.
A small, high-percentage bottle can deliver the same daily dose as a large, low-percentage one, just in fewer drops. A 10ml bottle of 10% holds more CBD than a 30ml bottle of 3%.
Full-spectrum oils carry the full range of plant compounds alongside the CBD, which some people find changes how a given mg amount feels compared with an isolate at the same strength.

Pharmacokinetic research also notes that how you take CBD affects how much of that labelled mg actually reaches your system, a point covered in more detail further down.

Which CBD strength band suits you: low, medium or high?

Strength bands give you a shortcut once you understand the mg-per-ml maths, but the labels “low”, “medium” and “high” only mean something once you attach numbers to them. The number that matters most is mg per drop, because that’s the size of each step you can take.

Low strength typically means 5% or under, which works out at anywhere from a fraction of a milligram to about 2.5mg per drop. These bottles sound beginner-friendly, but the trade-off is volume: reaching even 20mg a day from a 1% oil means 40 drops, and the per-mg price on weak bottles is usually poor. They suit people who genuinely want to micro-dose a milligram or two at a time, and not many others.

Medium strength, around 10% (100mg/ml), fits the largest group of people, including most beginners. At about 5mg a drop you get precision and value at the same time: two drops is a 10mg dose, four drops is 20mg, and you can adjust in 5mg steps. Our 10% Full Spectrum CBD Oil (1,000mg in a 10ml bottle, £25.99) sits squarely in this band, and it’s where we point most people starting out.

High strength, 20% and up, suits people taking 20mg or more a day. At about 10mg a drop, a 20% oil covers a typical daily dose in two or three drops, and the per-mg price improves: our 20% oil is 2,000mg for £37.99, noticeably cheaper per mg than buying two 10% bottles. The steps are coarser (10mg at a time rather than 5mg), which is the only real reason to prefer 10% while you’re still finding your level. Beyond drops altogether sit the syringe formats, 50% and 85%, which experienced users measure by volume rather than counting drops.

Reviews of CBD’s dose-response pattern suggest it can behave in a biphasic way in some contexts, meaning higher isn’t automatically better once you’ve found an effective range. Chasing the strongest format because it looks like better value can work against you if your actual daily need sits closer to 15mg than 150mg.

Full-spectrum and isolate products can also feel different at matching mg levels, since full-spectrum oils, explained in more detail here, carry additional plant compounds that some people report intensifying the perceived effect.

Shop the product

Full Spectrum CBD Oil

10% (1,000mg) or 20% (2,000mg) per 10ml bottle, about 5mg or 10mg of CBD per drop. Made in small batches in Bolton since 2018.

From £25.99Shop now

How do you calculate your CBD dose from the label?

The formula stays the same no matter which bottle sits on your shelf:

Divide total mg by bottle volume (ml) to get mg per ml.
Divide mg per ml by drops per ml (about 20, since a drop is roughly 0.05ml) to get mg per drop.
Multiply mg per drop by the number of drops you take to get your actual dose.

Working through four bottles shows how differently they behave:

300mg in 30ml (1%): 10mg/ml, roughly 0.5mg per drop. You’d need around 20 drops to reach a 10mg dose, which is a lot of squeezing for a modest amount.
1,000mg in 10ml (10%): 100mg/ml, about 5mg per drop. Two drops gets you to 10mg, four drops to 20mg, and a full 1ml dropper holds 100mg. Easy numbers to work with.
2,000mg in 10ml (20%): 200mg/ml, about 10mg per drop. One drop is a 10mg dose on its own, so counting stays trivial even at 30 or 40mg a day.
85% distillate: around 850mg/ml. Nobody doses this by the drop; it comes in a graduated syringe and 0.1ml is already about 85mg. Strictly for experienced users who know their level.

Capsules simplify all of this, since each one carries a fixed amount with no counting involved. Ours come in 40mg, 80mg and 120mg strengths: 40mg suits people starting on capsules, 80mg is the regular-user strength, and 120mg is for experienced users who already know their level. If you want finer steps than that, drops are the tool; once you know your dose, capsules make it effortless.

How should you titrate up from your starting dose?

“Start low and go slow” isn’t just cautious wording, it reflects the real spread in clinical dosing. Reviewed dosing literature shows studies have used amounts ranging from tens of milligrams up to several hundred a day, with no single figure that works for everyone. That variation is exactly why a fixed weekly plan beats guesswork.

A simple schedule looks like this:

Week one: take 10 to 20mg once daily, ideally at the same time each day. If you’re cautious or know you’re sensitive to new supplements, a first few days at 5 to 10mg is fine, but treat that as a toe in the water rather than a place to settle.
Week two: if you’ve noticed no change and no side effects, increase by 5 to 10mg.
Week three: repeat the increase only if needed, watching for the specific effect you’re targeting.
Beyond week three: hold at whatever dose is working. Resist the urge to keep climbing once you feel a difference.

Watch for concrete, specific signs rather than vague impressions: easier sleep onset, fewer waking episodes, a noticeable drop in tension or restlessness, or a change in how a nagging ache feels through the day. Mild side effects like drowsiness, a dry mouth, or slight digestive changes are worth noting, and anything more pronounced is a reason to pause and reduce your dose rather than push through it.

Body weight, metabolism, and how consistently you take your dose all shift the pace of titration, and so does the method: sublingual drops act faster than a swallowed capsule, so patience matters more with the latter.

Tip: Keep a simple daily note of dose, timing, and how you felt. Two weeks of consistent notes tells you more than switching products every few days ever will.

What does the FSA say about safe CBD intake, and what should you watch for?

The Food Standards Agency currently advises healthy adults to keep CBD intake from food supplements to about 10mg a day. That’s worth knowing, and in our view it’s also worth putting in context: it’s a precautionary figure rather than a reflection of real-world use. The FSA’s own advice was 70mg a day until autumn 2023, clinical research routinely uses doses in the hundreds of milligrams, and plenty of regular users settle somewhere between 25 and 100mg or more. Treat it as a cautious official reference point, not a maximum. The FSA’s business guidance also sets out what CBD sellers are expected to disclose about their products, including novel food compliance.

On tolerability, the WHO’s 2018 report found CBD is generally well tolerated in humans and showed no signs associated with abuse or dependence, a useful reassurance against some of the more alarmist claims floating around online.

That said, dose-related side effects do turn up in the literature, and they’re worth knowing before you start:

Mild drowsiness or fatigue, particularly at higher doses.
A dry mouth or subtle changes in appetite.
Digestive upset, including loose stools, at the top end of studied ranges.
Rare interactions with liver enzyme pathways (the CYP family) that also process many prescription medicines.

That last point matters more than it might seem. If you’re on prescription medication, especially anything metabolised through the liver, or you’re pregnant or breastfeeding, NHS guidance recommends checking with a GP or pharmacist first, since CBD can alter how those enzymes process other drugs. This isn’t a reason to avoid CBD altogether, but it is a reason to have that one conversation before you start titrating.

Which bottle strength should you actually buy?

Match the bottle to your target dose before you match it to price. A useful rule: pick a strength where your intended daily dose lands somewhere between two and eight drops. That’s enough drops to fine-tune by one without turning your morning into a counting exercise. On a 10% oil, that range covers 10 to 40mg a day; on a 20% oil, 20 to 80mg.

Two common mismatches to avoid:

Buying a weak bottle (say 300mg in 30ml) when you already know you need 30 to 40mg a day. You’ll be counting sixty-odd drops daily, which soon wears thin.
Buying a concentrated syringe format (50% or above) for your first try. Measuring a 10mg dose means judging hundredths of a millilitre, which makes fine control genuinely difficult until you know your level.

Beyond strength, a quick checklist worth running through:

Clear mg/ml or mg-per-drop labelling: the single most useful number on the packaging.
Honest testing: a good seller knows exactly how their CBD is tested. Ours is lab-tested at source, and we’re happy to share the certificates of analysis.
Storage and expiry guidance: potency drifts over time if oil is stored badly.
A track record: a brand that’s been trading for years with reviews to show for it has earned its label claims. We’ve been at this since 2018 and hold an Excellent rating on Trustpilot across 700+ reviews.

Tip: If you’re between two strengths, size down rather than up. It’s far easier to take more drops of a gentler oil than to split hairs over half a drop of something concentrated.

What we see most often when people get their CBD dose wrong

The most common mistake isn’t choosing the wrong band, it’s confusing strength with dose. The strongest format on the shelf looks like better value on paper, but it strips away the fine control that a beginner actually needs. We’ve had plenty of conversations with customers who bought a concentrated syringe expecting faster results, then struggled to measure anything smaller than a dose several times larger than they intended.

Our range is built to avoid exactly that trap: every bottle states its strength plainly (1,000mg or 2,000mg in a 10ml bottle), so working out a drop-by-drop dose doesn’t require a calculator held up to the label. What actually makes the difference for most people isn’t a bigger number on the bottle, it’s picking a sensible strength and sticking with it for a few weeks before judging whether it’s working.

Richard, Honest CBD Co

Find the right strength in the Honest CBD Co range

Once you know your target mg, matching it to a bottle is straightforward, because our range is a strength ladder. The Full Spectrum CBD Oil comes in 10% (1,000mg, £25.99) for measured starts and fine 5mg steps, and 20% (2,000mg, £37.99) for anyone settled at 20mg a day or more. If a fixed dose suits your routine better, our capsules in 40mg, 80mg and 120mg remove drop-counting entirely, from £19.99 for a 15-pack. Experienced users who measure by volume can step up to the 50% Amber Oil (around 2,500mg in a 5ml syringe, £25.99) or the 85% Distillate (about 850mg per ml, from £9.99). For a broader look before deciding, the full CBD oil collection lays out every strength side by side.

We’re a husband-and-wife business in Bolton, trading since 2018, making our own products in the UK in small batches, with an Excellent rating on Trustpilot across 700+ reviews. If you’re still weighing up strengths, start with the 10% oil and the two-drop 10mg dose this guide is built around, then let the weekly schedule above find your level.

This article is general information, not a substitute for advice from a qualified doctor.