This is a Dry Herb Equivalent Calculator

For converting herbal concentrates into dry herb equivalents


Add the amount of concentrated herbal extract in ml or g. Then drag the bar across to determine the concentration.

(Hint: you can also click on the bar and use the arrow keys to have more precision). 

This calculator will also work when trying to find the dosage from a desired amount of a specific constituent. 

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Dry Herb Equivalent Calculator

Amount of Concentrated Herbal Extract : ml or mg
Concentration: 0%

Dry Herb Equivalent = 0.00


Example: A ginseng extract is featured in a study for reducing mental fatigue.

They used 2g doses of a ginseng extract that was a 13% extract (the results yielded a weight 13% of the original herb weight). 

The study showed significant improvement of mental fatigue using the ginseng extract. In order to apply this, we must either use the extract itself, or find the equivalent in dried ginseng root. 

To find how much ginseng is needed to achieve these same results, enter the amount of extract used in the study (in this case 2g). 

Then move the slider over to the percent it was concentrated to (in our case 13%). 

The result gives us 15.38g. 

This means that a dose of 15.5g of ginseng root doses is needed to achieve the same results found in the study. (yes, this is a lot!). 


Other Uses For This Calculator:


It will also work for concentrates of a single compound or essential oil if you can find how much that compound is present in the herb naturally. 

For Example: Chrysin, a flavonoid found in passionflower, was shown to be effective for treating depression at a dose of 20mg/kg. You can use this information to deliver an effective dose for this condition suing the herbal calculator. If a person weighs 70kg, than this dose will be 70 x 20 = 1400mg of chrysin.

Now since we know that flavonoids (mainly chrysin) makes up about 2.5% of passionflower vine, we can use the calculator to find out how much of the dried herb (or 1:1 extract) we will need to deliver this same dose of flavonoids including chrysin. 

In the herbal extract box, we will enter 1400 for the amount of chrysin (herbal extract) we are looking to deliver. 

Next we will move the slider to the 2.5% value using the arrow keys for the most precision. 

We will find that this is in fact equal to 56 000g of dried passionflower. A virtually unachievable amount as you can see. This makes this dosage of chrysin unachievable from the dried herb itself, and will require concentration before being administered.

Dosing Calculators For Children:

Ausberger’s Rule

Birth onwards (based on weight)
(1.5 x weight in kg) + 10 = Percentage of adult dose


Clark's Rule

2-12 years of age

(weight in kg X adult dose)/67 = childs dose


Cowling's Rule

(Age of childs next birthday / 24) = percentage of the adult dose. 

Reference description (for justins purposes while building calculator) - "Divide the number of the child's next birthday by 24. Example: dosage for a child who is 3, turning 4 would be: 4 divided by 24 = .16, or 1/6 of the adult dosage."


Fried's Rule

For infants up to 2 years of age

(age in months x adult dose)/150 = childs dose


Salisbury's Rule

Up to 30 kg

(wieght in kg X 2) = percentage of adult dose to give


30+ kg

(weight + 30)= percentage of adult dose


Young's Rule

For infants up to 2 years 

(age in years X adult dose)/(age + 12) = childs dose


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