Fluid requirement vary with patient weight. To calculate maintenance fluid requirements, the following formula can be used:

• 4 ml/kg/h for the first 10 kg
• 2 ml/kg/h for the next 10 kg
• 1 ml/kg/h for every kg over 20 kg

Therefore a 70 kg patient using the calculation:

40+20+50=110

will require 110 ml/h