Maintenance Fluids (4-2-1)
Compute pediatric maintenance IV fluid rate using the Holliday-Segar 4-2-1 rule: 4 mL/kg/hr for the first 10 kg, 2 mL/kg/hr for the next 10 kg, and 1 mL/kg/hr for every kilogram thereafter.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Weight
- 70 kg
Result: Maintenance: 110 mL/hr (40 + 20 + 50)
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Weight
What this is
Sophie Well takes a weight in kilograms and returns the hourly rate along with the daily volume (the 100-50-20 daily equivalent), so a clinician can prescribe either an hourly drip or a 24-hour total without recomputing.
When to use it
Use this when prescribing maintenance fluids for an admitted pediatric patient, when checking that an existing order matches the weight on chart, or when a resident wants to confirm a back-of-envelope calculation before the order goes into the EHR. The 4-2-1 rule assumes a euvolemic patient at baseline; bolus replacement, ongoing losses, and dextrose strategy live outside this tool. Modern practice favors isotonic maintenance fluids (per AAP 2018 guidance) over the historical hypotonic default - the rate is the math; the fluid composition is a clinical decision.
How this is calculated
Holliday MA, Segar WE. Pediatrics 1957. 4-2-1 maintenance rule. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.
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