How do you calculate fluid therapy for a dog or a cat?
Add maintenance, the dehydration deficit and ongoing losses, then turn the total into ml/h and drops per minute. Enter the species and weight: the calculator uses the 2024 AAHA and Merck Veterinary Manual formulas.
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Patient
Maintenance
Dehydration
Under 5%: not detectable.
Ongoing losses
Weigh the pads: 1 g ≈ 1 ml.
Shock bolus
Dog: 15–20 ml/kg over 15 min. Reassess perfusion at the end.
Fluid
Isotonic and balanced. For shock, to replace the deficit and for short maintenance.
Contains calcium: do not run it in the same line as citrated blood. Lactate is processed by the liver.
Na 130 · Cl 110 · K 4 · Ca 2.7 · 273 mOsm/l · AAHA 2024 Fluid Therapy Guidelines, tabla 8
Drip set or pump
How do you calculate maintenance fluids for dogs?
Maintenance for a dog is 132 × kg^0.75 ml per day, per the 2024 AAHA guidelines. A 10 kg dog needs about 742 ml a day, 31 ml/h. Two other formulas: 60 ml/kg per day, or 30 × kg + 70, valid from 2 to 70 kg.
How do you calculate maintenance fluids for cats?
Maintenance for a cat is 80 × kg^0.75 ml per day, per the 2024 AAHA guidelines. A 4 kg cat needs about 226 ml a day, 9.4 ml/h. Cats overload more easily than dogs: recheck breathing, weight and edema often.
How do you calculate the dehydration deficit?
The deficit in ml is the dehydration % ÷ 100 × body weight in kg × 1000. A 12 kg dog at 8% has a 960 ml deficit, replaced over 12 to 24 hours on top of maintenance (2024 AAHA; Merck Veterinary Manual).
How do you calculate drops per minute?
Drops per minute = ml/h × drops per ml of the set ÷ 60. With a 20 drops/ml set, 30 ml/h is 10 drops per minute, one drop every 6 seconds. With a microdrip set (60 drops/ml), drops per minute equal ml/h.
How much fluid bolus is given for shock?
Dogs get 15 to 20 ml/kg and cats 5 to 10 ml/kg over 15 minutes, with a replacement fluid such as lactated Ringer's, Plasma-Lyte or 0.9% saline. Reassess perfusion before repeating (2024 AAHA).
What fluid rate is dangerous?
The hourly shock dose is 90 ml/kg/h in dogs and 60 ml/kg/h in cats; a maintenance or replacement rate should never reach it (Yagi, dvm360 2019). The calculator warns you when the rate gets there.
How to calculate fluid therapy for a dog or a cat
- Weigh the patient and work out maintenance: dog 132 × kg^0.75 and cat 80 × kg^0.75 ml per day.
- Estimate dehydration % from the signs and work out the deficit: % ÷ 100 × kg × 1000 ml.
- Divide the deficit by the hours to replace it (12 to 24) and add it to hourly maintenance.
- Add hourly losses from vomit and diarrhea.
- Turn the total into drops per minute: ml/h × drops per ml of the set ÷ 60.