Veterinary Flow Rate Calculator
Calculate IV fluid rates and drip counts for veterinary patients.
Enter the animal's weight in kilograms.
Standard Maintenance: 2-4, Surgery: 5-10.
10 gtt/ml (Macrodrip – Large Dogs)
15 gtt/ml (Standard Macrodrip)
20 gtt/ml (Macrodrip)
60 gtt/ml (Microdrip – Cats/Small Dogs)
Check the packaging of your IV administration set.
Default is 1 hour for flow rate calculation.
Total Fluid Volume per Hour:
0 ml/hr
Total Volume for Duration:
0 ml
Drip Rate (Drops per Minute):
0 gtt/min
Drip Rate (Drops per Second):
~1 drop every 0 sec
How to Calculate Veterinary IV Fluid Rates
Administering fluid therapy is a critical skill in veterinary medicine. Whether treating dehydration, maintaining blood pressure during anesthesia, or providing maintenance fluids, accuracy is paramount. This calculator assists veterinary technicians and veterinarians in determining the correct flow rate in milliliters per hour (ml/hr) and the corresponding drip rate in drops per minute (gtt/min).
Understanding the Inputs
- Patient Weight (kg): The weight of the animal is the primary factor in determining fluid volume. If you only have weight in pounds, divide by 2.2 to get kilograms.
- Desired Rate (ml/kg/hr): This is the dosage of fluid.
- Maintenance: Typically 2–4 ml/kg/hr for dogs and cats.
- Anesthesia/Surgery: Often starts at 5–10 ml/kg/hr, adjusted based on blood pressure and hydration status.
- Shock: Rates can be significantly higher (e.g., up to 90 ml/kg/hr for dogs) and are usually calculated as boluses.
- Drop Factor (gtt/ml): This value represents how many drops (gtt) it takes to equal 1 milliliter of fluid. This is determined by the specific IV administration set (tubing) you are using.
- Macrodrip sets: Usually 10, 15, or 20 gtt/ml. Used for patients >10kg.
- Microdrip sets: Always 60 gtt/ml. Used for patients <10kg or requiring precise slow rates.
The Formulas
If you prefer to double-check the math manually, here are the standard formulas used in this calculator:
1. Calculate Hourly Volume (ml/hr):
Weight (kg) × Rate (ml/kg/hr) = Total ml/hr
2. Calculate Drip Rate (gtt/min):
(Total ml/hr × Drop Factor) ÷ 60 minutes = gtt/min
3. Practical Counting (Seconds per Drop):
To manually set the rate on a gravity line without a pump, it helps to know how many seconds should pass between drops.
60 ÷ gtt/min = Seconds per drop
Example Calculation
Consider a 20 kg dog undergoing surgery with a prescribed rate of 5 ml/kg/hr using a standard 15 gtt/ml administration set.
- Volume: 20 kg × 5 ml/kg/hr = 100 ml/hr.
- Drip Rate: (100 ml/hr × 15 gtt/ml) ÷ 60 = 25 gtt/min.
- Manual Setting: 60 ÷ 25 = 2.4. You should see roughly 1 drop every 2.4 seconds (or roughly 5 drops every 12 seconds).