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Calcimator

Pediatric Dosing Calculator

Calculate age- and weight-adjusted medication doses for children using Young's, Clark's, and Fried's rules.

Inputs

years
lb

AAP: weight-based dosing standard; typical pediatric weights: 6 mo 7 kg; 1 yr 10 kg; 5 yr 18 kg; 10 yr 32 kg

mg

Results

Young's Rule Dose

166.7mg

Clark's Rule Dose

142.9mg

Fried's Rule Dose (infants)0mg
BSA-Based Dose213mg
Average (Young/Clark)154.8mg
How to Use This Calculator
  1. Enter child weight (kg) and age (years/months).
  2. Select the medication and review weight-based and age-based dose recommendations.
  3. Always verify with current Harriet Lane or BNFc guidelines — this tool is for reference only.

How the result changes with Adult Dose

Adult DoseYoung's Rule DoseClark's Rule Dose
501167mg143.1mg
1,751583.7mg500.3mg
3,2501,083.3mg928.6mg
4,5001,500mg1,285.7mg

What each input means

Child's Age
Age of the child in years. Use decimals for months (e.g., 0.5 = 6 months).
Child's Weight
Child's body weight in kilograms. Weight-based dosing (mg/kg) is standard for pediatrics per FDA pediatric labeling and AAP guidelines. Always verify calculated dose against maximum adult dose and product labeling.
Adult Dose
Standard adult dose of the medication in milligrams.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    Child's Age = 6, Child's Weight = 20, Adult Dose = 500 = 3 input(s) provided
  2. Calculate Young's Rule Dose
    Young's Rule Dose
    166.7 = 166.7
  3. Calculate Clark's Rule Dose
    Clark's Rule Dose
    142.9 = 142.9
  4. Calculate Fried's Rule Dose
    Fried's Rule Dose
    0 = 0
  5. Calculate BSA-Based Dose
    BSA-Based Dose
    213 = 213

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