Maintenance Fluid (Holliday-Segar)
Pediatric maintenance IV fluid rate using the 4-2-1 rule (Holliday-Segar method). Outputs hourly AND daily volumes with fluid type guidance and restriction condition flags.
🧮 Maintenance Fluid (Holliday-Segar) — Formula
🩺 Paediatric doses based on BNFc/AAP guidelines. Always confirm with a paediatrician.
📌Holliday MA, Segar WE. Pediatrics 1957 / NICE Guideline NG29 (2015) / PALS Guidelines 2020
📊 Quick Reference
| Input / Parameter | Description | Example Value |
|---|---|---|
| Weight (kg) | Current measured weight — never estimated for dosing | 18 kg |
| Date of birth | For exact age and corrected age calculation | 15 June 2022 |
| Gestational age at birth | For corrected age in preterm infants | 32 weeks |
| Height/length (cm) | For growth chart and IBW calculation | 105 cm |
| Dose (mg/kg) | Prescribed weight-based dose from protocol | 15 mg/kg (paracetamol) |
| Output dose (mg) | Calculated single dose — check against adult max | 270 mg |
| Percentile | Growth chart position vs age/sex reference | 25th centile (height) |
ℹ️ About This Calculator
The Maintenance Fluid (Holliday-Segar) is used by paediatricians, emergency physicians, and clinical pharmacists to calculate weight-based medication doses, assess child growth against reference standards, evaluate developmental status, or manage neonatal conditions. All reference values, dosing guidelines, and clinical thresholds are based on WHO/CDC paediatric growth standards, British National Formulary for Children (BNFc), and American Academy of Pediatrics (AAP) clinical practice guidelines.
Paediatric care requires specialised dosing and assessment approaches that cannot simply be derived by scaling adult values. Children's organ systems — particularly renal, hepatic, and neurological — mature throughout childhood, fundamentally changing drug pharmacokinetics, appropriate dose ranges, and physiological reference ranges at each age. Growth, developmental milestone assessment, and vaccination scheduling require age-referenced normative data that changes continuously from birth to adolescence. The Maintenance Fluid (Holliday-Segar) provides the validated, age-referenced calculations that make precise paediatric clinical assessment possible.
The specific formula, dose parameters, or reference charts used by this calculator are shown in the Formula section below. For paediatric drug dosing specifically, formula transparency is critical: a clinician who understands whether a dose is based on mg/kg, mg/m², or a fixed age-banded dose is better equipped to identify when a result seems unexpectedly high or low and to verify it before prescribing.
Critical dosing safety rules: all paediatric drug doses have an upper "adult maximum" ceiling — if a weight-based calculated dose exceeds the adult dose for that drug, give the adult dose, not the calculated weight-based dose. This ceiling protects against overdosing in large children and adolescents. Additionally, for children under 3 years and neonates, always verify doses with a paediatric pharmacist — physiological maturation means that standard weight-based doses appropriate for older children can be toxic in young infants.
For premature infants and neonates, always use corrected (adjusted) gestational age for growth chart plotting and developmental assessment until at least 2 years corrected age (for infants born before 32 weeks). Using chronological age for a premature infant generates false concerns about growth faltering and developmental delay — the correction accounts for the developmental stage appropriate to the infant's maturity, not the calendar age since birth.
All calculations run in your browser only. No child weight, date of birth, gestational age, or clinical data is transmitted to any server or stored in any database. These tools are designed for use by healthcare professionals in clinical settings. Parents using these tools for guidance should always confirm doses and developmental assessments with their child's paediatrician or pharmacist before acting on any result. When in doubt about a child's health, always seek immediate medical assessment.
📌Clinical Reference: Holliday MA, Segar WE. Pediatrics 1957 / NICE Guideline NG29 (2015) / PALS Guidelines 2020
📋 How to Use This Calculator
- 1
Record the child's current weight
Use the child's weight measured at the current visit in kilograms. For neonates and infants, use the most recent measured weight. Never estimate weight for drug dosing calculations in paediatrics.
- 2
Enter age and sex
For growth chart and developmental tools, enter the child's date of birth and current date. For premature infants, use corrected (adjusted) gestational age for growth plotting until the child reaches 2 years corrected age.
- 3
Input clinical measurements
For growth charts, enter height and head circumference. For jaundice tools, enter total serum bilirubin and gestational age at birth. For PECARN, enter clinical findings from examination.
- 4
Review the calculated dose or percentile
The tool returns the weight-based dose, growth percentile, or clinical risk classification. Cross-reference against the reference chart or published dose table for confirmation.
- 5
Confirm with a paediatrician or pharmacist
All paediatric doses must be confirmed by the treating paediatrician or a pharmacist experienced in paediatric dosing before administration. Parents should not adjust doses without professional guidance.
🎯 When to Use This Calculator
Routine well-child growth monitoring
Plot height, weight, and head circumference on WHO/CDC growth charts at each well-child visit. Identify children falling across centile lines for early investigation of growth faltering or excess.
Antipyretic dosing at every fever visit
Calculate exact paracetamol and ibuprofen doses by current weight before each fever visit to avoid both under-dosing (ineffective) and overdosing (hepatotoxicity risk).
PICU and emergency drug dosing
Use the paediatric emergency drug calculator to pre-calculate weight-based doses of resuscitation drugs (adrenaline, atropine, glucose) before a code to eliminate calculation errors under pressure.
Neonatal jaundice management
Apply the Bhutani nomogram to total serum bilirubin at specific ages (in hours) to identify neonates at high risk of requiring phototherapy before discharge.
Developmental milestone assessment
Calculate corrected gestational age for preterm infants before assessing developmental milestones. Failure to correct leads to false concerns about delay in premature infants.
💡 Clinical Pro Tips
Always use corrected (adjusted) gestational age for growth plotting and developmental assessment in premature infants until 2 years of chronological age for infants born before 32 weeks, and until 1 year for infants born 32–36 weeks. Failure to correct leads to false concerns about developmental delay in premature infants.
For paediatric drug dosing, the "maximum adult dose" is a hard ceiling — if a weight-based dose exceeds the adult dose, give the adult dose. A 40 kg child on paracetamol at 15 mg/kg = 600 mg — this is appropriate. A 50 kg teenager at 15 mg/kg = 750 mg — give 500–1000 mg (adult dose), not 750 mg.
Weight in paediatric emergency drug calculations can be estimated using the Broselow tape (length-based, colour-coded) or the formula: Weight (kg) ≈ 2 × (age in years + 4) for children 1–10 years. Pre-calculated Broselow-based dosing reduces errors under resuscitation stress significantly.
Neonatal jaundice risk zones on the Bhutani nomogram are highly time-sensitive — interpret bilirubin ONLY with the exact postnatal age in hours, not just days. A bilirubin of 18 mg/dL at 48 hours is high risk; the same level at 96 hours is low-intermediate risk.
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