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Dispensing Calculator (Formulation & Weighed Amount)

Enter the single dose, doses per day, number of days, and the formulation content (% or mg/g), and instantly get the total active drug and the actual amount of formulation to weigh out. Handy for estimating dispensing amounts of powders and oral liquids.

Input

Calculate the amount to dispense for powders, oral liquids, and similar formulations. From the single dose, doses per day, and number of days, it finds the total active drug required and divides by the formulation's content (potency) to give the actual amount of formulation to weigh out.

mg
x
days

How content is expressed

%

e.g. a 10% powder contains 100 mg of active drug per 1 g of formulation (= 100 mg/g).

Result

Formulation to weigh out

21g

Weighing a formulation with a 10% content ratio

Total active drug

2,100 mg

Total doses

21 doses

Daily amount (active drug)

300 mg

Calculation breakdown

ItemValue
Dose per administration (active drug)100 mg
Daily amount (dose x doses/day)300 mg
Total active drug (daily amount x days)2,100 mg
Formulation content ratio10 %
Amount to weigh (formulation)21 g

How it works

  • The total active drug (mg) is found as "dose (mg) x doses per day x number of days". The daily amount is "dose x doses per day", and the total number of doses is "doses per day x number of days".
  • The amount to weigh out (required formulation) is calculated as "total active drug / formulation content ratio". The content ratio is the proportion of active drug in the formulation (dimensionless).
  • Formulation content can be entered as "%" or "mg/g". A 10% powder contains 100 mg of active drug per 1 g of formulation (= 100 mg/g), so the content ratio is calculated as 0.10.
  • The dose you enter is the amount as the active drug (active ingredient), not the amount of the formulation itself. The actual dispensing amount including excipients must be considered separately.
  • Results are derived mechanically from the formulation, content, and dosing plan, and may differ from the actual weighed amount due to rounding, formulation specifications, or dispensing rules. Verification and auditing of prescriptions must always be performed by a qualified professional.
  • This tool provides rough estimates based on general formulas and is not a diagnosis or medical procedure. Always consult a physician for health-related decisions.