Maintenance Fluids Calculator (Holliday-Segar / 4-2-1 Rule)

Your details

Body weight of the patient. Use ideal body weight for obese patients, as excess adipose tissue does not proportionally increase fluid needs.
kg
The two methods agree closely. Holliday-Segar gives the total daily volume; the 4-2-1 rule gives a rounded per-hour infusion rate directly.
Daily maintenance volumeOlder Child (20-40 kg)
1,500mL/day

Holliday-Segar total 24-hour fluid requirement

Hourly infusion rate60mL/h
Fluid bolus (20 mL/kg)400mL
Weight used20kg
Daily volume (mL)1,500
Bolus dose (mL)400

Maintenance fluids for 20.0 kg: 1500 mL/day or 60.0 mL/h

  • At 20.0 kg, the Holliday-Segar daily requirement is 1500 mL, which is 62.5 mL/h as a continuous infusion.
  • The 4-2-1 rule gives a rounded hourly rate directly: 60.0 mL/h. It uses 4/2/1 in place of 4.17/2.08/0.83, so it approximates the Holliday-Segar hourly figure rather than matching it exactly.
  • A standard resuscitation bolus is 400 mL (20 mL/kg), given rapidly over 20-30 minutes.
  • Adjust for clinical status: febrile, burn, or critically ill patients need additional fluid beyond baseline maintenance. Restrict in patients with cardiac, renal, or hepatic dysfunction.

Next stepAlways reassess fluid orders at least every 24 hours based on urine output, vital signs, and serum electrolytes.

= Powered by OnlyCalculators