About this calculator
This calculator estimates routine pediatric maintenance fluid requirements from weight. It is useful for education and quick reference, but it does not calculate dehydration deficits, resuscitation boluses, electrolyte prescriptions, or fluid restrictions.
Children with kidney disease, heart disease, edema, abnormal sodium, critical illness, burns, postoperative needs, or neonatal fluid needs require individualized clinical orders.
Uses the Holliday-Segar maintenance fluid method: 100 mL/kg/day for the first 10 kg, 50 mL/kg/day for the next 10 kg, and 20 mL/kg/day for each kg above 20 kg; the hourly 4-2-1 rule is shown as an equivalent bedside estimate.
Source-mapped educational formula
Maintenance fluid formulas do not cover dehydration replacement, ongoing losses, boluses, electrolyte disorders, DKA, burns, surgery, renal disease, cardiac disease, or ICU care.
Formula and method
Daily fluid = 100 mL/kg for the first 10 kg + 50 mL/kg for the next 10 kg + 20 mL/kg for each kg above 20 kg. Hourly 4-2-1 estimate = 4 mL/kg/h for the first 10 kg + 2 mL/kg/h for the next 10 kg + 1 mL/kg/h above 20 kg.
Limitations and when not to rely on this result
- Maintenance fluid formulas do not cover dehydration replacement, ongoing losses, boluses, electrolyte disorders, DKA, burns, surgery, renal disease, cardiac disease, or ICU care.
- Children at risk of hyponatremia, fluid restriction, or rapid clinical change need clinician-directed orders and monitoring.
- Use local pediatric fluid protocols and laboratory monitoring when fluids are prescribed.
Frequently asked questions
What is the Holliday-Segar formula? +
It is a classic weight-based method for estimating maintenance water needs in children: 100/50/20 mL/kg/day across weight tiers.
Is this the same as IV fluid ordering? +
No. Real IV orders also require fluid type, electrolytes, glucose, clinical status, sodium risk, losses, and monitoring.
Does this calculate dehydration replacement? +
No. It estimates routine maintenance only. Dehydration deficit and resuscitation require separate clinical assessment.
When should I not use this estimate? +
Do not self-apply it for neonates, kidney or heart disease, fluid restriction, critical illness, burns, postoperative care, or abnormal electrolytes.
Why show both daily and hourly values? +
Daily totals are useful conceptually; hourly 4-2-1 rates are commonly used for bedside pump-rate estimates.