IV Fluid Rate Calculator for Dogs and Cats
Calculate maintenance, dehydration replacement, and shock fluid rates for dogs and cats. Get the answer in both mL/hr and drops per minute for the most common drip sets (10, 15, 20, and 60 drops/mL).
Species
Body weight
How to use this tool
Maintenance rate
Modern small-animal practice uses 2–3 mL/kg/hr as a baseline maintenance rate. The older "metabolic body weight" formula tends to overestimate for very small or very large patients; the linear 2–3 mL/kg/hr is more defensible.
Dehydration deficit
Estimate clinical dehydration by physical exam (skin tent, mucous membrane tackiness, eye position):
- <5%: Not detectable clinically (history only)
- 5–6%: Tacky mucous membranes, slight skin tent
- 7–8%: Definite skin tent, slow CRT, sunken eyes
- 10–12%: Pronounced skin tent, dull cornea, signs of shock
- >12%: Hypovolemic shock
Calculate the deficit volume: weight (kg) × % dehydration × 10 = deficit (mL). Typically replace over 12–24 hours added to maintenance.
Shock rate
For hypovolemic shock, give a shock-rate bolus: dogs 60–90 mL/kg (one full blood volume) or cats 40–60 mL/kg, in incremental boluses (1/4 of the total) over 15–20 minutes with reassessment after each bolus.
Frequently asked questions
What is the maintenance fluid rate for dogs and cats?
Common formulas: dog ≈ 60 mL/kg/day (or 132 × kg^0.75), cat ≈ 50 mL/kg/day (or 80 × kg^0.75). Always tailor to patient condition - cardiac patients get less, neonates more.
How do you calculate shock fluid rate?
Standard "shock dose" is one blood volume per hour, given in aliquots: dog 60-90 mL/kg, cat 40-60 mL/kg. Give 1/4 to 1/3 of the calculated dose over 15 minutes, reassess, repeat as needed - never bolus the full dose in one go.
How is fluid deficit calculated?
Deficit (L) = body weight (kg) × % dehydration / 100. A 20 kg dog at 7% dehydrated has a 1.4 L deficit. Replace over 6-24 hours depending on patient stability, on top of maintenance and ongoing losses.
How do mL/hr convert to drops per minute?
Drops/min = (mL/hr × drop factor) ÷ 60. Common drop factors: macrodrip 15 drops/mL or 20 drops/mL, microdrip 60 drops/mL. The calculator outputs both so you can match whichever drip set you have.