Pediatric Dehydration Percentage Calculator
Enter pre-illness and current weight to calculate dehydration percentage, classify severity, and estimate fluid deficit with rehydration guidance.
Patient Weights
Weight Unit
Weight before onset of illness
Weight at time of assessment
Medical disclaimer: This tool is for educational reference only. Results must be verified by a licensed clinician before any clinical decision, treatment, or fluid administration.
Enter pre-illness and current weights to calculate dehydration.
Dehydration Severity
%
dehydration by body weight
0%
5%
10%
15%+
Mild
Moderate
Severe
Weight Lost
Fluid Deficit
Pre-illness Weight
Current Weight
Clinical Guidance
Summary
Enter pre-illness and current weight to calculate dehydration percentage, classify severity, and estimate fluid deficit with rehydration guidance.
How it works
- Enter the child's pre-illness (baseline) weight in kilograms or pounds.
- Enter the child's current weight after illness onset.
- Dehydration % is computed as (pre-illness weight − current weight) / pre-illness weight × 100.
- The fluid deficit in mL equals weight loss in kg × 1000.
- Severity is classified: mild <5%, moderate 5–9%, severe ≥10%.
- Rehydration guidance is displayed for the classified severity tier.
Use cases
- Estimate dehydration severity in a child presenting with vomiting and diarrhea.
- Calculate fluid deficit in mL to guide oral rehydration therapy planning.
- Quickly classify dehydration as mild, moderate, or severe for triage decisions.
- Cross-check a bedside dehydration assessment during a pediatric consultation.
- Teach nursing students about weight-based dehydration percentage calculations.
- Track rehydration progress by comparing serial weights during inpatient care.
Frequently Asked Questions
Last updated: 2026-07-24 ·
Reviewed by Nham Vu