Dogs and cats
AAHA 2024
Fluid therapy calculator
Allometric maintenance rate, dehydration deficit, and drip rates for four giving sets. Every figure prints the arithmetic that produced it, so the number can go in the record with its working. Free, no signup.
Patient
1% is a 10 mL/kg loss. Leave at 0 for maintenance only.
Total IV rate
Enter a patient weight to compute the rate.
- Maintenance
- — mL/hr132 × kg0.75
- Deficit
- — mLkg × 0% × 10
- Drip rate
Drops per minute for four giving sets at the total rate Giving set gtt/min 10 gtt/mL — 15 gtt/mL — 20 gtt/mL — 60 gtt/mL —
The working
Four formulas, and where each one comes from
Nothing here is proprietary. These are the published formulas, printed so you can check the calculator against them rather than trust it.
- Maintenance
132 × kg0.75 mL/day (dog) · 80 × kg0.75 mL/day (cat)
Allometric scaling rather than a linear mL/kg/day rate, which is what the guideline recommends across the size range general practice sees. The same guideline gives rules of thumb of 2–6 mL/kg/hr for dogs and 2–3 for cats. Neither edition explains the 0.75 exponent; both print the formula and cite DiBartola.
- Deficit
kg × dehydration % × 10 = mL
1% dehydration is a 10 mL/kg loss. This page replaces it evenly over 24 hours; a sicker patient is often corrected faster, which is a clinical decision this calculator does not make for you.
- Ongoing losses
not calculated here
The guideline’s framework is maintenance plus deficit plus ongoing losses. Vomiting, diarrhoea, polyuria, drains and third-spacing are estimated at the cage side and added on top of the figure this page gives you — the total below is not the whole prescription.
- Drip rate
mL/hr × gtt/mL ÷ 60 = gtt/min
The drop factor is printed on the giving set. Four common sets are shown; read the one in your hand rather than the one you expect.
Maintenance coefficients and the rules of thumb are from the 2024 AAHA Fluid Therapy Guidelines for Dogs and Cats, Table 9. They are unchanged from the 2013 AAHA/AAFP guidelines (Davis et al., J Am Anim Hosp Assoc 49(3):149–159), Table 3. The 2024 edition offers three interchangeable maintenance formulas and declines to rank them; this page uses the allometric one.
In the app
This page needs a signal. The app does not
Fluid therapy is one of the nine calculators in Workup, and in the app all nine sit on the device with the 326-drug catalog and the clinical references — so they work in a treatment area with one bar. VHS/VLAS cardiac measurement and the feline USG Predictor are the exception: both run on cloud inference and need a connection.
Clinical use
A decision-support tool for licensed veterinary professionals, not a substitute for clinical judgment. This page gives maintenance and deficit only — ongoing losses, rate, route and duration are yours to set. Verify every figure against the patient in front of you before administering fluids. Workup is not FDA- or USDA-cleared as a medical device.