How Calculations Work

This documentation is intended to guide you through the various calculators available on the site. These calculators are all driven by client-side JavaScript, ensuring transparency of calculations. To review the code behind the calculations, simply right-click anywhere on the page and select "view page source".

Pediatric Dose Calculator
Our Pediatric Dose Calculator is specifically designed to compute Intravenous (I.V.) dosages for children aged between 0 to 12 years and weighing from 3 to 45 kg. The calculated dosages are displayed up to 2 decimal places, and they are rounded off to the nearest .0, .25, .5, or .75 for practicality. However, please be aware that this rounding-off does not apply to final dosages that are under 1.

Additional Features

HR and RR: The calculator provides standard estimates of heart rate (HR) and respiratory rate (RR) for a healthy, awake, and resting child.

Tidal Volume (VT): The VT is calculated based on a standard of 6 - 8 ml/kg.

Maintenance Fluids: These are calculated using a variant of the Holliday-Segmar formula. Note that this calculation does not take into account factors like preoperative fasting (NPO) or perioperative blood loss.

For weights 0 - 10 kg: 3 ml/kg/hr
For weights 11 - 20 kg: 30 ml + 1 ml/kg/hr
For weights above 20 kg: 40 ml + 0.5 ml/kg/hr

DC Cardioversion: The dosage for DC cardioversion is calculated by multiplying the child's weight (in kg) by 4.

ETT and LMA Sizes: Provided for uncuffed tubes. Please be aware that the suggested sizes might not fit all patients.

Local Anesthetic Calculator
This calculator assists in determining weight-based local anesthetic dosages (expressed in mg/kg). If the input weight is in pounds (lb), it will automatically convert this to kilograms (kg) by multiplying the lb weight by 0.45359237. The final dosages are then displayed up to 2 decimal places and are rounded off to the nearest .0, .25, .5, or .75.

Hourly Fluids Calculator
The Hourly Fluids Calculator estimates the hourly fluid requirements for patients weighing 60kg/132 lbs or more. It takes into account the patient's body weight, the duration of preoperative fasting, and the estimated surgical fluid losses. The calculation assumes NPO losses replaced over 3 hours, with 50% in the first hour, and 25% for each of the subsequent two hours.

The calculator uses the Holliday-Segmar formula and applies the following rates:

For weights 0 - 10 kg: 4 ml/kg/hr
For weights 11 - 20 kg: 40 ml + 2 ml/kg/hr
For weights above 20 kg: 60 ml + 1 ml/kg/hr

As in other calculators, if the input weight is in lb, it converts this to kg (by multiplying the lb weight by 0.45359237) before estimating fluid needs.

IBW, LBW, and BMI Calculator
This calculator provides estimates for Ideal Body Weight (IBW), Lean Body Weight (LBW), and Body Mass Index (BMI) using the following formulas:

IBW: For males, it is the height (in cm) - 100; for females, it's the height (cm) - 105.
LBW: For males, LBW = 0.407 * weight + 0.267 * height - 19.2; for females, LBW = 0.252 * weight + 0.473 * height - 48.3.