mg (milligrams)
ml (10 mg/ml)
ml (50 mg/ml)
ml (100 mg/ml)
Understanding Medication Dosage Calculations
Accurate medication dosage is crucial for patient safety and treatment efficacy. This calculator is designed to assist healthcare professionals and caregivers in determining the correct amount of medication to administer based on patient weight and the prescribed drug's concentration.
The fundamental principle behind many weight-based dosage calculations is:
This formula provides the target amount of the active drug substance needed for the patient.
However, medications are often supplied in liquid formulations (e.g., solutions, suspensions) where the concentration of the active ingredient is expressed as milligrams per milliliter (mg/ml). In such cases, an additional step is required to convert the total dosage into the volume (in milliliters) that needs to be administered.
The formula for this conversion is:
Volume to Administer (ml) = Total Dosage (mg) / Concentration (mg/ml)
This calculator automates these calculations. When you select a medication formulation, it uses the corresponding concentration to determine the final volume to administer.
How it Works:
Patient Weight (kg): This is the primary factor determining the dose. It's essential to use the most accurate and up-to-date weight measurement.
Medication Dosage (mg/kg): This is the dose of the active drug prescribed by a physician, calculated per kilogram of body weight.
Medication Formulation: This selection determines the concentration of the medication available. Different formulations have different amounts of active drug per unit volume (e.g., per milliliter). The calculator uses standard concentrations:
10 mg/ml: Each milliliter contains 10 milligrams of the active drug.
50 mg/ml: Each milliliter contains 50 milligrams of the active drug.
100 mg/ml: Each milliliter contains 100 milligrams of the active drug.
Example Scenario:
Let's say a doctor prescribes a medication for a child weighing 25 kg. The prescribed dosage is 7 mg/kg. The available liquid medication comes in a formulation of 50 mg/ml.
Step 1: Calculate Total Dosage Needed Total Dosage = 25 kg × 7 mg/kg = 175 mg
Step 2: Calculate Volume to Administer Volume = 175 mg / 50 mg/ml = 3.5 ml
Therefore, 3.5 ml of the medication should be administered. This calculator will provide this result instantly upon entering the values.
Disclaimer: This calculator is intended as a tool for reference and educational purposes. Always consult with a qualified healthcare professional for medical advice and before making any decisions related to your health or treatment. Dosage calculations should be double-checked by a second qualified person before administration.
function calculateDosage() {
var patientWeight = parseFloat(document.getElementById("patientWeight").value);
var medicationDosage = parseFloat(document.getElementById("medicationDosage").value);
var medicationFormulation = document.getElementById("medicationFormulation").value;
var resultDiv = document.getElementById("result");
// Clear previous results
resultDiv.innerHTML = ";
resultDiv.style.display = 'none';
// Input validation
if (isNaN(patientWeight) || patientWeight <= 0) {
alert("Please enter a valid patient weight in kilograms.");
return;
}
if (isNaN(medicationDosage) || medicationDosage 0) {
volumeToAdministerMl = totalDosageMg / concentrationMgPerMl;
resultDiv.innerHTML =
volumeToAdministerMl.toFixed(2) + " ml" +
"Total Dosage: " + totalDosageMg.toFixed(2) + " mg | " + formulationText + "";
} else {
// Should not happen with valid switch cases, but for safety
resultDiv.innerHTML = "Error calculating volume.";
}
} else {
resultDiv.innerHTML =
totalDosageMg.toFixed(2) + " mg" +
"" + formulationText + "";
}
resultDiv.style.display = 'block';
}