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Pediatric Maintenance Fluid Calculator
Enter a weight to get the hourly maintenance IV rate by the 4-2-1 rule and the daily volume by Holliday-Segar: 4, 2 and 1 mL/kg/h for the first 10 kg, the next 10 kg and each kg above 20. Not for newborns; order deficits and losses separately.
Enter child’s weight in kg. Example: 12.5.
For clinicians and students. The result is a starting rate for a child who needs IV maintenance; adjust it to the child's condition, urine output and electrolytes.
Maintenance fluid formulas
| Weight | 4-2-1 rule (hourly) | Holliday-Segar (daily) |
|---|---|---|
| First 10 kg | 4 mL/kg/h | 100 mL/kg/day |
| Next 10 kg (11–20 kg) | + 2 mL/kg/h | + 50 mL/kg/day |
| Each kg above 20 | + 1 mL/kg/h | + 20 mL/kg/day |
Worked example, 22 kg: hourly = 4 × 10 + 2 × 10 + 1 × 2 = 62 mL/h; daily = 1,000 + 500 + 20 × 2 = 1,540 mL/day.
How to calculate maintenance IV fluids
- Enter the child’s current weight and choose kg or lb.
- Press Calculate to get the hourly 4-2-1 rate (mL/h) and the Holliday-Segar daily volume (mL/day).
- Choose the fluid (isotonic with dextrose and potassium as indicated for most children) and write the order.
- Order deficits, boluses and ongoing losses separately, and reassess weight, urine output and electrolytes.
Which fluid to use: AAP 2018
The AAP clinical practice guideline recommends isotonic maintenance fluids with appropriate potassium chloride and dextrose for patients 28 days to 18 years old, because hypotonic fluids carry a higher risk of hyponatremia. The guideline covers medical and surgical patients on the ward and in intensive care.
It does not apply to neonates younger than 28 days or in the NICU, adolescents older than 18, or children with neurosurgical disorders, heart disease, liver disease, cancer, kidney dysfunction, diabetes insipidus, large watery diarrhea losses or severe burns. Those children need individual plans.
When the calculated rate needs adjusting
- Deficits and ongoing losses: replace them with separate orders rather than raising the maintenance rate, so each can be stopped or changed on its own.
- Hyponatremia risk: acutely ill and postoperative children can retain free water, which is why the AAP favors isotonic fluids. Some children need fluid restriction, and heart and kidney disease need individual plans. Follow local policy.
- Obesity and large adolescents: the formula uses actual weight and keeps rising with weight, so it can overestimate needs.
- Fever and insensible losses: may raise needs; adjust to hydration status and urine output rather than a fixed percentage.
- Monitoring: weigh the child, track intake and output, and check sodium, potassium and glucose after starting fluids and after any change.
Common mistakes
- Entering pounds as kilograms (the result will be 2.2 times too high).
- Adding a deficit or bolus into the maintenance rate instead of ordering it separately.
- Leaving the rate unchanged when urine output, weight or sodium changes.
- Using the formula for neonates, who need day-of-life protocols.
Maintenance fluid rates by weight
Calculated with the same formulas as the tool above (4-2-1 hourly, Holliday-Segar daily).
| Weight | Hourly (4-2-1) | Daily (Holliday-Segar) |
|---|---|---|
| 5 kg | 20 mL/h | 500 mL/day |
| 10 kg | 40 mL/h | 1,000 mL/day |
| 12 kg | 44 mL/h | 1,100 mL/day |
| 20 kg | 60 mL/h | 1,500 mL/day |
| 22 kg | 62 mL/h | 1,540 mL/day |
| 30 kg | 70 mL/h | 1,700 mL/day |
| 40 kg | 80 mL/h | 1,900 mL/day |
| 60 kg | 100 mL/h | 2,300 mL/day * |
* Above 2,000 mL in 24 hours: see the upper limit below.
Example order: "Isotonic maintenance fluid with dextrose and potassium as indicated at [hourly rate] mL/h; recheck electrolytes per local policy."
Upper limit for adolescents
The formula keeps rising with weight. NICE guideline NG29 advises that over 24 hours males rarely need more than 2,500 mL and females rarely more than 2,000 mL of maintenance fluid, so the calculator flags results above 2,000 mL per 24 hours (by either method) for a second look.
Frequently asked questions
It gives an hourly rate: 4 mL/kg/h for the first 10 kg of weight, 2 mL/kg/h for the next 10 kg, and 1 mL/kg/h for every kg above 20. A 22 kg child gets 40 + 20 + 2 = 62 mL/h.
It gives a daily volume: 100 mL/kg/day for the first 10 kg, 50 mL/kg/day for the next 10 kg, and 20 mL/kg/day for every kg above 20. It comes from Holliday and Segar’s 1957 estimate of water needed per calorie burned, and the 4-2-1 rule is its hourly version.
The 4-2-1 rule is a rounded hourly version of Holliday-Segar, so the two don’t line up exactly: 4-2-1 multiplied by 24 hours is a little lower than the daily formula for smaller children and a little higher for larger ones. Either is acceptable as a starting point; use one consistently and adjust to the child.
The AAP 2018 guideline recommends isotonic solutions with appropriate potassium chloride and dextrose for children 28 days to 18 years, because they lower the risk of hyponatremia compared with hypotonic fluids. It excludes neonates under 28 days and children with certain conditions; follow local policy for those groups.
The formula keeps adding 1 mL/kg/h for every kg, so it overestimates needs in large adolescents and adults. NICE NG29 notes that over 24 hours, males rarely need more than 2,500 mL and females rarely need more than 2,000 mL. Use adult maintenance guidance for adult-sized patients.
No. Maintenance covers normal daily needs only. Give boluses for shock or hypovolemia (for example 20 mL/kg isotonic crystalloid), and order deficit replacement and ongoing losses (vomiting, diarrhea, drains) as separate, documented orders.
Holliday-Segar is based on actual weight, which can overestimate needs in children with obesity. Some hospitals use an adjusted or ideal weight instead. Follow your local policy and monitor electrolytes and fluid balance.
No. Term and preterm newborns have fluid needs that change by day of life. Use your neonatal unit’s protocol.
References
- Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics. 1957;19(5):823-832. pubmed.ncbi.nlm.nih.gov/13431307/
- Feld LG, Neuspiel DR, Foster BA, et al. Clinical Practice Guideline: Maintenance Intravenous Fluids in Children. Pediatrics. 2018;142(6):e20183083. doi.org/10.1542/peds.2018-3083
- National Institute for Health and Care Excellence. Intravenous fluid therapy in children and young people in hospital (NG29), recommendation 1.4.1. www.nice.org.uk/guidance/ng29/chapter/Recommendations
- Cavari Y, Pitfield AF, Kissoon N. Intravenous maintenance fluids revisited. Pediatr Emerg Care. 2013;29(11):1225-1228. pubmed.ncbi.nlm.nih.gov/24196097/