💧 Pediatric Maintenance IV Fluids: The 4-2-1 Rule Made Simple

A simple explanation of calculating pediatric maintenance IV fluids by weight using the 4-2-1 (Holliday-Segar) rule, with a worked example and safety notes.

Calculating pediatric maintenance IV fluids is a daily task in pediatric and emergency settings. The most widely used and simplest approach is the 4-2-1 rule, derived from the Holliday-Segar method, based on the child's weight in kilograms.

What are maintenance fluids?

They are the amount of fluid needed to replace normal daily losses (urine, respiration, skin) to keep fluid balance, not to correct dehydration or acute losses, which are calculated separately.

The 4-2-1 rule (hourly rate)

| Weight band | Fluid rate |

|---|---|

| First 10 kg | 4 mL/kg/hour |

| Second 10 kg (11–20) | 2 mL/kg/hour |

| Each kg above 20 | 1 mL/kg/hour |

> Add the results of the three bands to get the total hourly rate.

Worked example

A child weighing 26 kg:

• First 10 kg: 10 × 4 = 40 mL/hour
• Second 10 kg: 10 × 2 = 20 mL/hour
• Remaining 6 kg: 6 × 1 = 6 mL/hour
• Total = 66 mL/hour (≈ 1584 mL/day)

Important safety notes

• The rule is for maintenance only; dehydration and shock are added on top.
• Fluid type and glucose/electrolyte content depend on the child's condition.
• Monitor for signs of fluid overload and hyponatremia.
• In infants and critically ill children calculations may differ; follow your institution's protocol.

Try it now: Use the [Pediatric Maintenance IV Fluids Calculator (4-2-1 rule)](https://www.medclac.com/#open=pediatric_maintenance_fluids) to get the hourly and daily rate instantly.

Disclaimer: This content is for educational guidance only and does not replace professional medical consultation.