About the Cephalexin For Cats Dosage Calculator
Cephalexin is a first-generation cephalosporin antibiotic that veterinarians commonly prescribe for cats to treat bacterial skin infections, urinary tract infections, and other susceptible infections. This calculator converts your cat's body weight and the veterinarian's prescribed mg/kg rate into a per-dose amount in milligrams, the total dose across a full day, and the equivalent number of capsules or tablets at the product strength you have on hand.
The dosing formula
Veterinary references such as the Merck Veterinary Manual cite an oral cephalexin range of 15 to 35 mg per kilogram of body weight per dose for cats, given every 6 to 12 hours. Many veterinarians start around 22 mg/kg twice daily. The exact rate within that range, and how often it is given, is set by the prescribing veterinarian based on the type and severity of infection. Written out:
- Dose (mg) = body weight in kg × prescribed mg/kg
- Capsules/tablets per dose = dose (mg) ÷ product strength (mg) (commonly 250 mg capsules, or a compounded liquid for smaller cats)
- Total daily dose (mg) = dose per administration × doses per day
- If you weigh your cat in pounds, the calculator first converts using 1 kg = 2.20462 lb.
Understanding the inputs
Enter your cat's current body weight and choose lb or kg. Enter the prescribed dose in mg/kg exactly as your veterinarian specified it — this calculator does not choose a rate for you, since the correct rate depends on the infection being treated. Select how many times a day the medication is given, and enter the strength printed on the capsule, tablet, or liquid label so the count is accurate.
Interpreting the results
The highlighted card shows the milligrams to give at each administration. The other cards show how many capsules or tablets that equals, the running total for a full day, and where your prescribed rate sits within the standard 15-35 mg/kg reference range used across veterinary guidance, so you can sanity-check the number your vet gave you.
This tool performs the arithmetic only. Always confirm the exact dose, frequency, and treatment duration with your veterinarian before giving cephalexin or any other medication.