Free veterinary calculator
Fluid therapy calculator.
Allometric maintenance rate, dehydration deficit, and drip rates for dogs and cats. Runs in your browser — no signup, no install.
Patient
Estimated deficit. 1% dehydration = 10 mL/kg replacement.
Results
Enter a patient weight to compute maintenance rate, deficit, and drip rates.
Maintenance uses the allometric formula recommended by the AAHA / ISFM fluid therapy guidelines: 132 × kg0.75 mL/day for dogs, 80 × kg0.75 mL/day for cats. Surface-area scaling is more accurate than linear mL/kg/day across the size range vets see in practice. Refs: Davis et al. 2013 AAHA Fluid Therapy Guidelines; Goggs & Boag 2017.
Workup has seven of these built in.
The Workup mobile app includes fluid therapy plus six other clinical calculators — CRI, chemo BSA, transfusion, RER, HHS, and Pro-Sal — alongside AI-powered VHS/VLAS cardiac measurement and the USG Predictor. Try the app with a 30-day free trial.
Clinical use: This calculator is a decision-support tool for licensed veterinary professionals. It is not a substitute for clinical judgment. Verify all rates against the patient’s individual case before administering fluids. Workup is not FDA- or USDA-cleared as a medical device.