Pediatric Fluid Calculator
Holliday-Segar maintenance fluids for children.
Maintenance only. It does not include replacing an existing deficit or ongoing losses, and requirements change with fever, burns, tachypnoea, cardiac failure or SIADH.
Maintenance fluid rate
56 mL/hour
1400 mL per day
Isotonic fluid with glucose is now recommended for maintenance in most children; hypotonic solutions fell out of favour after evidence linked them to hyponatraemia.
How the Pediatric Fluid Calculator works
The Holliday-Segar method, published in 1957, estimates maintenance fluid needs from body weight in three tiers. It remains the standard starting point in paediatrics, usually remembered as the 4-2-1 rule for the hourly rate.
Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.
Frequently asked questions
What is the 4-2-1 rule?
4 mL/kg/hour for the first 10 kg of body weight, 2 mL/kg/hour for the next 10 kg, and 1 mL/kg/hour for every kilogram beyond 20. A 25 kg child needs 40 + 20 + 5 = 65 mL/hour.
How does this relate to the daily figure?
The daily equivalent is 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10, and 20 mL/kg thereafter. The hourly rule is simply that figure divided by 24 and rounded, which is why 100 becomes 4 rather than 4.17.
When do maintenance fluids need adjusting?
Fever, burns, tachypnoea and gastrointestinal losses increase requirements; cardiac failure, renal impairment and SIADH reduce them. Maintenance also does not include replacing an existing deficit or ongoing losses, which are calculated separately.
Which fluid should be used?
Isotonic fluid with glucose is now recommended for maintenance in most children. Hypotonic solutions fell out of favour after evidence linked them to hyponatraemia. The choice is a clinical decision and varies by national guideline.