THE NUMORIX GUIDE
How to use the Drug Dosage Calculator
Last reviewed September 14, 2026
What this calculator does
The engine multiplies the entered body weight by the entered dose rate: total dose in mg = weight in kg * dosage in mg/kg.
Formula and method
The engine multiplies the entered body weight by the entered dose rate: total dose in mg = weight in kg * dosage in mg/kg. It rounds the product to two decimals and shows the multiplication step.
Variables and inputs
Weight is in kilograms and dosage is in milligrams per kilogram. The form does not ask for a medication name, concentration, route, frequency, age, indication, maximum dose, or organ-function adjustment, so the result is only a unit calculation.
Worked example
For 70 kg and a prescribed rate of 5 mg/kg: total dose = 70 * 5 = 350.00 mg. That arithmetic does not establish that 5 mg/kg is an appropriate dose or that 350 mg can be safely administered.
How to interpret the result
The result answers one narrow question: what amount follows from the two numbers entered. It may represent a single dose only if a qualified prescriber has already specified the drug, dose basis, timing, and units.
Common mistakes to avoid
Confirm whether the order is mg/kg, mg/kg/day, or a fixed dose; do not confuse mg with mcg; and convert pounds to kilograms before entering weight. Check the medication concentration before converting milligrams into milliliters or tablets.
Assumptions and limitations
The engine has no medication-specific safety checks, maximum-dose cap, renal or hepatic adjustment, age or pediatric rule, route, frequency, concentration, interaction, or diagnosis logic. It accepts a negative dosage rate and only rejects nonpositive weight in the UI. Never use it to select or change a medication dose without a prescriber or pharmacist.