Medication Dose by Weight Calculator
Weight-based dosing with volume per dose.
Enter your values
Enter the body weight in kg.
Enter the dose in mg/kg.
Enter the concentration in mg per 5 ml.
Enter the doses per day you are working with.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Dose per administration
- 270 mg
- Volume per dose
- 11.3 ml
- Total daily dose
- 1080 mg
- Daily volume
- 45 ml
Working
- 118 kg x 15 mg/kg = 270 mg
Quick answer
Weight-based dose is mg per kg times body weight; volume is that dose divided by the concentration.
volume = (dose mg/kg x weight) / concentration
At a glance
| What it does | Weight-based dosing with volume per dose. |
|---|---|
| Category | Health |
| Inputs needed | Body weight, Dose, Concentration, Doses per day |
| Main output | Dose per administration |
| Formula | volume = (dose mg/kg x weight) / concentration |
| Cost | Free — no sign-up, no download |
How to use the Medication Dose by Weight Calculator
- 1Enter the patient weight in kilograms.
- 2Enter the prescribed mg/kg dose and the product concentration.
- 3Always confirm against the prescription and product label before administering.
Inputs explained
- Body weight(kg)
- Enter the body weight in kg.
- Dose(mg/kg)
- Enter the dose in mg/kg.
- Concentration(mg per 5 ml)
- Enter the concentration in mg per 5 ml.
- Doses per day
- Enter the doses per day you are working with.
Worked example
Using the values the calculator loads with:
Inputs
- Body weight18 kg
- Dose15 mg/kg
- Concentration120 mg per 5 ml
- Doses per day4
Results
- Dose per administration270 mg
- Volume per dose11.3 ml
- Total daily dose1080 mg
- Daily volume45 ml
- 18 kg x 15 mg/kg = 270 mg
Frequently asked questions
Is this a substitute for a prescription?
No. It is an arithmetic aid; dosing decisions belong to a qualified prescriber.
What about maximum daily dose?
Check the product ceiling separately — weight-based maths can exceed it in larger patients.
What do I need to enter into the Medication Dose by Weight Calculator?
Just 4 values: body weight, dose, concentration, doses per day. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Medication Dose by Weight Calculator work out the answer?
Weight-based dose is mg per kg times body weight; volume is that dose divided by the concentration. It applies the formula volume = (dose mg/kg x weight) / concentration and shows the working so you can check each step by hand.
Is the Medication Dose by Weight Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.