# Pediatric Dose Calculator (Young / Clark / mg·kg⁻¹ / BSA)

Estimate a pediatric drug dose using one of four methods: (1) Young's rule (age-based) — Child dose = Adult dose × age / (age + 12); (2) Clark's rule (weight in pounds) — Child dose = Adult dose × weight(lb) / 150; (3) mg/kg per-weight regimen (the modern first-line method) — Child dose = dosePerKg × weight(kg); (4) BSA method (Mosteller) — Child dose = Adult dose × BSA_child / 1.73, with BSA = √(height·weight/3600). These are empirical approximations; modern practice prefers drug-specific mg/kg or mg/m² regimens derived from pediatric trials and verified against pediatric references and the approved labeling. Not medical advice.

> Canonical page: https://elysiatools.com/en/tools/pediatric-dose-calculator

- **Category:** Health

- **Keywords:** pediatric dose, child dose, Young's rule, Clark's rule, mg/kg, body surface area, BSA, Mosteller, weight-based dosing, pharmacokinetics, pk, drug, medicine

## Overview

The Pediatric Dose Calculator estimates a child dose using Young's rule, Clark's rule, an mg/kg regimen, or the Mosteller BSA method. Results are empirical estimates and must be checked against drug-specific pediatric references, approved labeling, and a qualified healthcare professional.

## Inputs

- **Calculation Method** (select)
- **Adult dose (mg)** (number): Standard adult dose. Required for Young's, Clark's, and BSA methods.
- **Child age (years)** (number): Child age in years. Required for Young's rule.
- **Child weight (kg)** (number): Child weight in kilograms. Required for mg/kg and BSA methods; also used by Clark's rule (auto-converted from kg).
- **Child height (cm, BSA method only)** (number): Child height in centimeters. Required for the BSA method.
- **Dose per kg (mg/kg, mg/kg method only)** (number): Per-kilogram drug regimen. Required for the mg/kg method.
- **Decimal Places** (number)

## When to use

- Compare an age-based or weight-based estimate with a documented pediatric dosing reference.
- Calculate a dose from a drug-specific mg/kg regimen and the child's weight.
- Estimate a BSA-based dose when the child's height, weight, and adult dose are available.

## How it works

- Choose Young's rule, Clark's rule, mg/kg, or BSA from the Calculation Method menu.
- Enter the inputs required for the selected method, such as adult dose, age, weight, height, or dose per kg.
- The calculator applies the selected formula and rounds the child dose to the chosen number of decimal places.
- The result is returned as JSON with the estimated dose, method, formula, and model description.

## Use cases

- Check the arithmetic for an age-based pediatric dose estimate using Young's rule.
- Apply a documented mg/kg regimen to a child's measured weight.
- Calculate a Mosteller body surface area estimate for comparison with a BSA-based dosing reference.

## Frequently asked questions

### Which pediatric dose methods are supported?

The calculator supports Young's rule, Clark's rule, mg/kg dosing, and the Mosteller BSA method.

### What inputs does the mg/kg method require?

It requires the dose per kg in mg/kg and the child's weight in kilograms.

### Does Clark's rule use kilograms or pounds?

Clark's rule uses weight in pounds. The calculator accepts weight in kilograms and converts it automatically.

### What inputs are required for the BSA method?

The BSA method requires an adult dose, child weight in kilograms, and child height in centimeters.

### Is this calculator medical advice?

No. It provides empirical estimates only. Verify dosing with current pediatric references, approved labeling, and a qualified healthcare professional.

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