IV Maintenance Fluids Calculator

Calculate pediatric and adult maintenance fluid rates using the 100/50/20 rule.

Patient Inputs

Gender Actual Weight

Height

Auto-switch to IBW when BMI ≥ 30 (if height + gender provided) Force IBW for all calculations Show hourly rate

Holliday–Segar method: 100 mL/kg (first 10 kg) + 50 mL/kg (next 10 kg) + 20 mL/kg for each kg beyond 20. IBW uses Devine formula (50/45.5 + 2.3 × (inches − 60)). BMI is estimated when height is provided.

Maintenance Rate

Actual Weight (kg)—

Ideal Body Weight (kg)—

Weight Used (kg)—

BMI—

Maintenance Volume (mL/day)—

Maintenance Rate (mL/hr)—

Rounded (nearest 5 mL/hr)—

Bag Planning (2 L/day)—

Copyable Order

Clinical Considerations

Always reassess fluid status, renal function, and ongoing losses; adjust maintenance orders accordingly.
Consider sodium content, glucose requirements, and electrolyte supplementation based on patient context.
For overweight adolescents and adults (>40 kg), a 1 L bolus may be appropriate if clinically indicated.
Verify compatibility with comorbidities (e.g., CHF, CKD) and institution-specific policies.