“Before you compare two hydrogen water bottles, put their numbers in the same units. Then check how those numbers were measured. That is where a useful comparison starts.”
Sam, Research Scientist at iBottle
One bottle says 3,000 PPB. Another says 3 PPM. Which has the higher hydrogen concentration?
Neither. Those numbers describe the same concentration, provided they use the same measurement basis.
This is where I would start if you were asking me to help choose a bottle. Get the units straight first, then look at the report behind them. Once those details are clear, it is much easier to see what you are comparing.
The short answer: PPB, PPM and mg/L
PPB means parts per billion. PPM means parts per million. Divide PPB by 1,000 to get PPM: 2,500 PPB = 2.5 PPM.
For dilute water using mass-based PPM, that is approximately 2.5 mg/L—2.5 milligrams of dissolved hydrogen per litre. The approximation assumes the water density is close to 1 kg/L.
Keep one distinction in mind: mg/L is a concentration. Milligrams per bottle also depends on how much water is in it. I’ll walk you through both below.
Illustration for the unit guide. The worked examples below explain the numbers.
PPB to PPM: keep this table beside the product page
Changing from PPB to PPM changes how you write the figure. It leaves the concentration exactly the same.
PPB ÷ 1,000 = PPM. PPM × 1,000 = PPB.
| PPB | PPM | Approximate mg/L in dilute water* |
|---|---|---|
| 500 | 0.5 | 0.5 |
| 1,000 | 1 | 1 |
| 1,500 | 1.5 | 1.5 |
| 2,500 | 2.5 | 2.5 |
| 3,000 | 3 | 3 |
| 5,000 | 5 | 5 |
*The mg/L column assumes mass-based PPM and water density close to 1 kg/L.
My advice: pick one unit for your comparison and stick to it. If you write down 3,000 PPB for one bottle and 3 PPM for another, the extra zeros can make a simple comparison look confusing.
What does mg/L actually tell you?
A report showing 2 mg/L of dissolved hydrogen is telling you there are 2 milligrams per litre of that water at the time of measurement.
Why say PPM is only approximately mg/L? Mass-based PPM means milligrams per kilogram of the mixture. mg/L means milligrams per litre. A litre of dilute water weighs about a kilogram, which makes the numbers approximately equal. The US Geological Survey explains this relationship and why density matters.
For a buying comparison, the practical step is simple: check that the figure refers to dissolved molecular hydrogen in water. A PPM reading for a gas mixture or another substance answers a different question. NIST’s guidance on units explains why the quantity being measured should be stated clearly.
How much hydrogen is in the whole bottle?
Once you have the concentration in mg/L, you need the actual water volume.
Dissolved hydrogen mass (mg) = concentration (mg/L) × water volume (L). This follows the definition of mass concentration: mass divided by volume.
Here is a hypothetical example: 300 mL of water measured at 2 mg/L.
- Convert the water volume to litres: 300 mL ÷ 1,000 = 0.3 L.
- Multiply: 2 mg/L × 0.3 L = 0.6 mg of dissolved hydrogen.
With 600 mL at that same measured concentration, the total would be 1.2 mg. Twice the water, twice the calculated hydrogen mass. The concentration remains 2 mg/L.
Use the fill volume stated for the test. A bottle labelled “500 mL” may not have been tested with 500 mL inside it. This calculation describes the sample when it was measured; it does not tell you how much to drink.
What I would check before trusting the headline number
The units are the easy part. Now open the test report and see what the number belongs to.
✅ The exact bottle and cycle
Check the model, version, cycle duration and number of cycles. Put those details beside the result. A single-cycle reading and a result after repeated cycles describe different procedures.
✅ The water and the timing
Look for the fill volume, water type, temperature, cap position and time between generation and sampling. If a detail is missing, ask for it before treating two tests as directly comparable.
✅ The measurement method
Read how dissolved hydrogen was measured, including any calibration, repeat readings or uncertainty information. Our hydrogen water testing guide takes you through the procedure and demonstrations.
✅ Average, peak or one reading?
An average summarises a specified set of readings. A peak identifies a maximum within the stated test. Keep the label attached to the figure—you need it to understand what is being claimed.
If the report also gives a total in milligrams, check which concentration and volume it uses. An average concentration and a peak concentration can produce different totals when you do the multiplication.
You can open the published iBottle+ laboratory report and read its result labels, test conditions and calculation notes yourself.
A higher concentration and a higher total can belong to different samples
Consider these two hypothetical samples. They are examples to explain the maths, not bottle test results.
| Sample | Stated concentration | Water volume | Calculated hydrogen mass |
|---|---|---|---|
| A | 2,500 PPB ≈ 2.5 mg/L | 300 mL = 0.3 L | 2.5 × 0.3 = 0.75 mg |
| B | 2 PPM ≈ 2 mg/L | 500 mL = 0.5 L | 2 × 0.5 = 1 mg |
Sample A has the higher concentration. Sample B has more total dissolved hydrogen because it contains more water.
Which bottle would I choose? I would still want to see the test procedures, cycle time and size. These two calculations alone cannot settle that decision.
My advice: use the number, then read the evidence
Convert the units, check the actual fill volume and read the test conditions. Those three steps give you a much clearer comparison.
If you are choosing between our models, keep the iBottle and iBottle+ specifications beside this guide. For the broader buying decision, read our Australian hydrogen water bottle comparison.
PPB and PPM questions, answered
Is 1,000 PPB the same as 1 PPM?
Yes, when both express the same kind of concentration or fraction. Divide PPB by 1,000 to convert it to PPM.
Does a higher PPB number mean more hydrogen?
It means a higher concentration when the dissolved-hydrogen measurements use the same basis. For total hydrogen mass, you also need the measured water volume.
Can I convert PPM straight into milligrams per bottle?
First check the measurement basis and fill volume. For dilute water with mass-based PPM, treat PPM as approximately mg/L, then multiply by the volume in litres.
Where can I see how iBottle tests hydrogen water?
Start with our testing guide, then read the published iBottle+ laboratory report. Keep the report’s result labels and calculation notes with any figures you compare.
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