Using the MDmama Medication Calculator: 4 steps for safety

This free calculator was created independently with the sole purpose of helping caregivers feel more confident in administering fever and pain medications, and is not sponsored or funded by any pharmaceutical company or brand.

You may see familiar brand-name products pictured throughout the calculator simply to make medications easier to recognize. Generic versions work just as well, so please choose whatever works best for your child and your budget.

Disclaimer: While great care has been taken to build and test this calculator for accuracy, it is very important to confirm the calculated dose against the product label and verify that your child’s measured weight is appropriate for their age using WHO growth reference charts. Ultimately, caregivers are responsible for confirming that the medication, concentration, dose, and weight entered are correct before giving a medication. By using this calculator, you acknowledge that it is provided for educational and informational purposes only and that I cannot accept liability for errors, misuse, or any harm resulting from its use.

Step 1: Check for red flags

Read my blog post, "When does your child with a fever need to see a doctor?" to learn the REDFLAGS that mean you should take your child to the Emergency Room right away.

Step 2: Weigh your child

Although the calculator does allow you to enter your child’s age only, it is most accurate to dose medication based on your child’s actual weight when possible.

Babies should have a dry diaper and no clothing. Older children should wear as little clothing as possible and no shoes.

Compare the weight with the correct WHO table to make sure you weighed your child accurately:

​View WHO Weight Reference Charts for Canada

The tables show the average weight (50th percentile) for each age, along with the smaller (3rd percentile) and larger (97th percentile) ends of the spectrum. So, if you know your child is a little small compared to their peers, you should expect their weight to fall between the 50th and 3rd percentile. If you know they are very small for their age, you would expect it to be closer to the 3rd percentile than the 50th percentile. Make sense? If you want the actual charts with the full spectrum of percentiles, they can be found here.

👆Note! The tables list weights in kilograms (kg), not pounds (lbs). ​To change pounds into kilograms, divide the weight in pounds by 2.2.

Example: 44 lb ÷ 2.2 = 20 kg

⚠️ Does your child’s weight seem reasonable for their age according to the reference chart? If the number is surprising:

1. Make sure you are using kilograms, not pounds.

2. Babies should have a dry diaper and no clothing. Older children should wear as little clothing as possible and no shoes.

3. Put the scale on a firm, level floor and weigh your child again.

4. If the number is still surprising, ask a healthcare provider before using the calculator.

Step 3: Check the medication

Check the package carefully and identify the medication and exact concentration or strength shown on the label. For example, it may say mg, mg/mL, or mg/5 mL.

⚠️ Warning! Different products may contain different amounts of medicine, even when the brand name looks similar.

👀This is where to look for the medication strength (dose or concentration) on the package:

Step 4: Check the result

⚠️ Compare the calculator’s result with the recommended dose on the product label. Here are a few examples of commonly used products:

🤔 If the doses are very different, repeat steps 2-4 above, and try the calculation again.

🛑 If the doses are still very different after repeating steps 2-4, ask a pharmacist or qualified healthcare provider before administering any medication.

👆And remember:

1. Do not give more than the maximum number of doses allowed in 24 hours (this is included on the product label as well as in the MDmama calculator).

2. Use the syringe or measuring cup that comes with liquid formulations.

3. Keep medications out of reach of children! These medications are colourful and tasty and can result in serious harm if ingested in large quantities.