What is the Holliday-Segar method for pediatric fluid calculation?

The Holliday-Segar method calculates daily maintenance fluid requirements in children using weight bands: 100 mL/kg for the first 10 kg, plus 50 mL/kg for the next 10 kg, plus 20 mL/kg for each kg above 20 kg. For example, a 25 kg child needs (10×100) + (10×50) + (5×20) = 1600 mL/day, or 67 mL/hr.

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Pediatric Calculators

Q: How is pediatric drug dosing calculated?

Most pediatric drugs are dosed by body weight (mg/kg) or body surface area (mg/m²). The calculated dose is then checked against a maximum adult dose to avoid overdosing in larger children. Our Pediatric Dose Calculator covers both methods with built-in maximum dose safety caps based on BNF for Children and Harriet Lane Handbook references.

Q: What is a normal APGAR score?

APGAR scores range from 0 to 10. A score of 7–10 at 1 minute is considered normal and reassuring. A score of 4–6 indicates moderate depression requiring stimulation and possible oxygen. A score of 0–3 indicates severe depression requiring immediate resuscitation. The 5-minute score is more prognostically significant than the 1-minute score.

Specialist clinical tools for neonates, infants, children, and adolescents. From APGAR scoring in the delivery room to weight-based antibiotic dosing on the ward — all built on WHO, CDC, and AAP clinical guidelines with age-specific safety checks.

WHO / AAP guidelines Age-specific ranges Max-dose safety caps PDF reports

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Pediatric Dose Calculator

Weight-based (mg/kg) and BSA-based (mg/m²) dosing for common pediatric medications. Covers antibiotics, antivirals, antipyretics, anticonvulsants, and more — with maximum dose safety caps and frequency scheduling.

🔥 Most Used Use tool

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Growth Chart Percentile

Plot height, weight, head circumference, and BMI-for-age on WHO (0–5 years) and CDC (2–20 years) growth charts. Calculates Z-score, exact percentile, and stunting / wasting / overweight classification.

🔥 Popular Use tool

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Vaccine Schedule

Enter a child's date of birth to generate a personalised immunisation schedule based on CDC and WHO recommended childhood vaccination programs. Highlights overdue, due now, and upcoming vaccines by age.

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APGAR Score

Neonatal wellbeing assessment at 1 and 5 minutes. Scores appearance, pulse, grimace, activity, and respiration with colour-coded interpretation, resuscitation decision pathway, and documentation-ready printable report.

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Pediatric Fluid Requirement

Holliday-Segar method for daily maintenance fluid calculation. Outputs mL/day and mL/hr with the three weight-band breakpoints clearly shown. Also calculates deficit and replacement volumes for dehydration management.

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Pediatric Age Bands

Different clinical tools, reference ranges, and dosing thresholds apply to each age group.

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Neonate

0–28 days

APGAR · Fluid calc

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Infant

1–12 months

WHO charts · Dosing

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Toddler

1–3 years

WHO charts · Vaccines

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Child

3–12 years

CDC charts · Dosing

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Adolescent

12–18 years

CDC charts · BMI %ile

💧 Quick Holliday-Segar Fluid Estimate For full calculator with deficit/replacement → open tool

Child's Weight

Enter weight above to see maintenance fluid requirements.

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Dosing Safety Notice: Pediatric drug dosing calculations should always be verified against your local formulary (BNF for Children, Harriet Lane Handbook, or local pharmacy guidelines) before administration. Maximum dose caps are included as a safety check but do not replace clinical judgement or pharmacist verification. Always double-check weight in kg — accidental dosing in lbs is a known error source.

Drug Classes Covered in the Pediatric Dose Calculator

Amoxicillin Co-amoxiclav Cefalexin Azithromycin Clarithromycin Trimethoprim Nitrofurantoin Paracetamol / Acetaminophen Ibuprofen Phenobarbitone Phenytoin Sodium valproate Acyclovir Oseltamivir Prednisolone Dexamethasone Salbutamol Metronidazole Gentamicin Vancomycin Iron (oral) + more

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Maximum Dose Safety Caps

Every drug in the dose calculator includes a maximum dose ceiling. If a weight-based calculation exceeds the adult maximum, the tool flags it and defaults to the safe upper limit.

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WHO + CDC Growth Standards

Our growth chart tool uses WHO MGRS data for under-5s and CDC 2000 charts for ages 2–20, with Z-score calculated using the LMS method — the same standard used by UNICEF and national health systems.

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Personalised Vaccine Schedule

Enter a date of birth and our tool generates a complete immunisation schedule with dates for each vaccine, overdue alerts, and catch-up guidance — something no competitor offers for free.

About Pediatric Clinical Calculators

Pediatric medicine requires age-specific, weight-specific, and development-stage-specific calculations that cannot be safely extrapolated from adult references. Children are physiologically distinct across each developmental stage — neonates, infants, toddlers, school-age children, and adolescents have different pharmacokinetics, normal vital sign ranges, reference growth parameters, and immunological profiles.

Pediatric Drug Dosing — Why It's Different

Adult drug doses cannot simply be scaled down by weight. Neonates and infants have immature hepatic enzyme systems (particularly CYP3A4 and glucuronidation pathways), larger volumes of distribution for water-soluble drugs, and reduced renal clearance. These factors mean that mg/kg dosing in neonates often results in a lower dose per kg than in older children, not a higher one. Our Pediatric Dose Calculator uses age-stratified reference doses from BNF for Children, the Harriet Lane Handbook, and published evidence-based guidelines.

Growth Assessment: WHO vs. CDC Charts

The WHO Multicentre Growth Reference Study (MGRS) charts, based on children raised under optimal conditions across six countries, represent how children should grow under ideal circumstances — making them a prescriptive standard. The CDC 2000 growth charts, based on US reference populations, are more descriptive — showing how children in the US actually grow. The AAP recommends WHO charts for children under 2 years and CDC charts for ages 2–20. Our Growth Chart Percentile tool applies both automatically based on the child's age.

APGAR Score — Delivery Room Assessment

The APGAR score, developed by anaesthesiologist Virginia Apgar in 1952, remains the standard neonatal assessment tool worldwide. The 1-minute score guides immediate resuscitation decisions, while the 5-minute score has greater prognostic significance for neurological outcomes. A 10-minute score may be recorded if the 5-minute score is below 7. Our APGAR Score tool generates a documentation-ready report suitable for birth records.

Holliday-Segar Fluid Calculation

The Holliday-Segar method (1957) estimates daily maintenance fluid requirements based on metabolic rate, which correlates with body weight in three bands:

Weight	Fluid Rate	Example
First 10 kg	100 mL/kg/day (4 mL/kg/hr)	10 kg → 1000 mL/day
Next 10 kg (10–20 kg)	50 mL/kg/day (2 mL/kg/hr)	+500 mL/day
Each kg above 20 kg	20 mL/kg/day (1 mL/kg/hr)	+20 mL/kg above 20

Note that the Holliday-Segar method provides a starting estimate. Actual fluid needs vary significantly with fever, losses, renal function, and clinical condition. Always titrate to clinical response and electrolyte monitoring.

Frequently Asked Questions

How is pediatric drug dosing calculated safely? +

Most pediatric drugs are dosed by actual body weight in mg/kg. The calculated dose is then checked against a maximum dose (usually the adult dose) to prevent overdosing in larger children. For obese children, dosing weight may use ideal body weight or adjusted body weight depending on the drug's pharmacokinetics. Our dose calculator applies all three weight types with clear labelling. Always verify against your local formulary and consult a pharmacist for complex cases.

What is a normal APGAR score at birth? +

A 1-minute APGAR score of 7–10 is reassuring and normal. A score of 4–6 indicates moderate neonatal depression requiring stimulation and supplemental oxygen. A score of 0–3 indicates severe depression requiring immediate resuscitation (bag-mask ventilation and possibly chest compressions). The 5-minute score is prognostically more important — a persistently low score at 5 minutes is associated with increased risk of hypoxic-ischaemic encephalopathy and neurological morbidity.

What is the difference between WHO and CDC growth charts? +

WHO charts (used for ages 0–5 years) describe optimal growth in healthy, breastfed children raised under ideal conditions — they represent a prescriptive international standard. CDC charts (used for ages 2–20 years) are based on the US reference population and are more descriptive of how American children actually grow. The AAP recommends WHO charts for children under 2 and CDC charts from age 2 onwards. Our growth chart tool switches automatically based on the age you enter.

Which vaccines should my child have received by age 2? +

By age 2, the CDC recommended schedule includes: Hepatitis B (3 doses), DTaP (4 doses), Hib (3–4 doses), PCV13 (4 doses), IPV (3 doses), MMR (1 dose), Varicella (1 dose), Hepatitis A (2 doses), and influenza (annually). Use our Vaccine Schedule tool to generate a personalised schedule by date of birth, with current and overdue vaccines highlighted.

Can these tools be used for premature infants? +

Premature and low-birthweight neonates require corrected gestational age for growth chart plotting (subtract weeks of prematurity from chronological age). Our growth chart tool supports corrected age input. Drug dosing in premature neonates is highly specialised — doses, frequencies, and formulations often differ significantly from term neonates and older infants. Always consult a neonatologist or neonatal pharmacist for premature infant dosing.

Related Tools on MediCalc Pro

For drug concentration and volume conversion alongside dose calculation, see Medication Dose Converter. For BSA-based dosing reference, see the BSA Calculator. For neonatal scoring in obstetric contexts, see APGAR in Women's Health. For IV drip rate calculation from fluid volumes, see IV Drip Rate Calculator.

References & Guidelines

World Health Organization. Child Growth Standards: Methods and Development. WHO Press, 2006.
Kuczmarski RJ, et al. "CDC Growth Charts: United States." Advance Data. 2000;(314):1-27.
Holliday MA, Segar WE. "The maintenance need for water in parenteral fluid therapy." Pediatrics. 1957;19(5):823-832.
Apgar V. "A proposal for a new method of evaluation of the newborn infant." Curr Res Anesth Analg. 1953;32(4):260-267.
Paediatric Formulary Committee. BNF for Children. BMJ Publishing Group, 2024.
Robertson J, Shilkofski N. The Harriet Lane Handbook. 21st ed. Elsevier, 2023.

⚠️ Medical Disclaimer: Pediatric calculators are provided for educational and informational purposes only. Drug doses must be verified against your local formulary and confirmed by a qualified pharmacist or prescriber before administration. Never adjust a child's medication based solely on an online tool.