Version July 2025
| Age | Weight | Replacement fluid volume |
| <4 months | <5 kg | 200 to 400 mL |
| 4 to 11 months | 5 to 8 kg | 400 to 600 mL |
| 12 to 23 months | 8 to 11 kg | 600 to 800 mL |
| 2 to 4 years | 11 to 16 kg | 800 to 1200 mL |
| 5 to 14 years | 16 to 30 kg | 1200 to 2200 mL |
| >15 years | >30 kg | 2200 to 4400 mL |
Patients with moderate volume depletion are estimated to have lost 5 to 10% of their body weight (ie, 50 to 100 mL of fluid per kg). The total fluid deficit should be replete within the first 3 to 4 hours of presentation.
If weight is known, 100 mL/kg of fluid can be administered. Ongoing losses, if severe, should be incorporated into replacement phase. Fluids should never be restricted. For infants <6 months receiving standard oral rehydration solutions (ORS), provide an additional 100 to 200 mL of water; this is not needed for patients receiving hypo-osmolar ORS.