Calculating the correct rate for enteral nutrition (tube feeding) is a critical task for clinicians, caregivers, and patients. The primary goal is to ensure the patient receives their prescribed daily caloric and nutritional requirements over a specific timeframe without causing gastrointestinal distress.
The Mathematical Formula
The calculation follows a straightforward logical progression:
Determine Total Daily Volume (mL): Divide the total daily caloric goal (kcal) by the formula's caloric density (kcal/mL).
Example: 2000 kcal ÷ 1.2 kcal/mL = 1,667 mL total.
Determine Hourly Rate (mL/hr): Divide the total daily volume by the number of hours the feeding will run.
Example: 1,667 mL ÷ 24 hours = 69.4 mL/hr.
Common Formula Concentrations
Enteral formulas vary in "thickness" or caloric density. Knowing which one you are using is essential for accuracy:
1.0 kcal/mL: Standard formula, usually provides the most free water.
1.2 – 1.5 kcal/mL: Often used for patients requiring fluid restriction or higher energy needs.
2.0 kcal/mL: Highly concentrated, used for severe fluid restriction (e.g., renal or heart failure).
Types of Feeding Schedules
This calculator can be adjusted based on the feeding method prescribed by your medical professional:
Continuous Feeding: Run via a pump over 24 hours. This is common in hospital settings to maximize tolerance.
Cyclic Feeding: Run over a shorter period (e.g., 12 or 16 hours), often at night. This allows the patient more mobility during the day.
Bolus Feeding: Administered in large volumes several times a day (like meals). For bolus calculations, set the hours to 1 and divide the resulting volume by the number of daily "meals."
The Importance of Free Water
While enteral formulas contain water, they rarely meet a patient's total hydration needs—especially concentrated formulas (1.5+ kcal/mL). The "Water Content" result in our calculator provides an estimate of the moisture within the formula itself. Patients typically require additional water flushes before and after feedings or medications to meet their total fluid requirements and keep the tube clear.
Disclaimer: This tool is for educational purposes only. Always follow the specific prescription provided by a registered dietitian or physician. Do not adjust feeding rates or formula types without medical supervision.