Practitioner Zone · Dose & ratio math
Herbalist Calculators
A set of practical herbalist calculators — children’s dosing rules, extract-ratio and dry-herb equivalents, tincture-making and alcohol dilution, infusion strength, dropper conversions, and capsule filling.
A collection of small, no-nonsense calculators for everyday herbal work — converting doses, building tinctures, and brewing to strength. Everything runs in your browser; nothing is sent anywhere. Jump to a tool, or scroll through.
Educational reference for qualified practitioners — not a prescription or a substitute for clinical judgment. Spot an error, or want a tool added? Get in touch.
Extract Ratio Equivalent
Liquid extracts are labeled as a herb-to-liquid ratio. A 1:5 tincture is 1 g of
dried herb in every 5 mL; a 2:1 concentrate packs 2 g into every 1 mL. So each mL
carries herb ÷ liquid grams of herb. Enter a volume and ratio to see the
dried-herb equivalent — and convert the same dose between ratios, concentrates included.
Related: Liquid Herb Dosages
Assumes the usual weight-to-volume convention (1 g dried herb per ratio mL). Real extracts vary with menstruum and herb; use this as a planning estimate.
Tincture Making
For a maceration at ratio 1:R, the menstruum is herb weight × R
(e.g. 100 g at 1:5 needs 500 mL). Then split that menstruum into your high-proof spirit and water
to hit a target alcohol strength: spirit = menstruum × target% ÷ spirit%,
and the rest is water.
Related: Liquid Herb Dosages · Herbs by Part
Assumes dried herb and ideal mixing (alcohol/water volume contraction is ignored — close enough for tincturing). Fresh herb carries its own water and shifts the final strength.
Alcohol Dilution
Blend two strengths to hit a target — Pearson’s square. Leave the weaker one at 0% to dilute a spirit with plain water, or set it to another spirit’s strength to blend two.
Related: Tincture Making
Dry Herb Equivalent
Convert a concentrated extract into the weight of dried herb it represents — handy for reproducing the doses used in research. Enter the amount of extract, then the concentration: the percentage the extract weighs relative to the original dried herb.
Related: Nootropic Dosage Guide
A 13% extract means the extraction yielded a weight 13% of the starting herb, so 2 g of it represents 2 ÷ 0.13 ≈ 15.4 g of dried herb. The result keeps your entered unit and shows the mg ⇔ g conversion so it can’t be misread by 1000×.
Infusion / Decoction Strength
How strong is your brew? Enter the dried herb and the water it steeped (infusion) or simmered (decoction) in. A standard medicinal strength is around 1:20. One cup is taken as 240 mL.
Related: Herbal Tea Dosages · Tea Types
Drops ↔ mL ↔ tsp
Translate a dose between drops, millilitres, and spoons. Droppers vary — the usual rule is about 20 drops per mL for a water-thin tincture, but thicker glycerites run fewer; adjust if you’ve counted your own.
Related: Liquid Herb Dosages
1 tsp = 5 mL · 1 tbsp = 15 mL.
Capsule Filling
How many capsules a dose takes depends on the capsule size and how densely the powder packs. Pick a size for a typical fill weight, then fine-tune the milligrams if you’ve weighed your own — herb powders vary a lot in density.
Related: Herbs by Part
Typical powdered-herb fills: 000 ≈ 1000 mg · 00 ≈ 600 mg · 0 ≈ 450 mg · 1 ≈ 300 mg · 2 ≈ 250 mg · 3 ≈ 200 mg. Approximate — weigh a few to calibrate.
Children’s Dosing
Six traditional rules estimate a child’s dose as a fraction of the adult dose, from age or body weight. Enter the child’s age first, then weight and the adult dose — every rule fills in at once so you can compare. The rule(s) appropriate for the age and weight you entered are marked Fits; faded rows mean the value falls outside that rule’s intended range. The rules don’t all agree — treat the spread as a sanity-check, not a single answer.
Related: Herbal Tea Dosages · Liquid Herb Dosages
All six rules
Show the formulas
Augsberger’s (birth onwards, by weight): (1.5 × weight in kg) + 10 = % of adult dose
Clark’s (~2–12 yrs, by weight): (weight in kg × adult dose) ÷ 67 = child’s dose
Cowling’s (by age): (age at next birthday ÷ 24) = fraction of adult dose
Fried’s (infants up to ~2 yrs): (age in months × adult dose) ÷ 150 = child’s dose
Salisbury’s (≤30 kg): (weight in kg × 2) = % of adult dose · (>30 kg): (weight in kg + 30) = % of adult dose
Young’s (~2–12 yrs): (age in years × adult dose) ÷ (age + 12) = child’s dose