Cat Diphenhydramine Dosage Calculator

Calculate the cat diphenhydramine dose for mild allergies or motion sickness, expressed in both tablet and liquid forms.

914.1K uses Updated · 2026-05-12 Runs locally · zero upload
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How to Use Cat Diphenhydramine Dosage Calculator

The Cat Diphenhydramine Dosage Calculator helps you turn 1–2 mg/kg cat dosing into tablets or millilitres.

  1. Verify the product — Use plain diphenhydramine only — combination products with acetaminophen are fatal.
  2. Enter weight — The dose is 1–2 mg/kg every 8–12 hours.
  3. Pick tablet or liquid — Liquid is easier for cats under 3 kg.
  4. Watch for side effects — Drowsiness is expected; agitation or vomiting means stop and call your vet.

Formula & Theory — Cat Diphenhydramine Dosage Calculator

Cat dosing is based on a published 1–2 mg/kg range:

dose_mg = weight_kg × 1.5
tablets = dose_mg ÷ tablet_strength_mg
mL = dose_mg ÷ liquid_concentration_mg_per_mL

Use Cases for Cat Diphenhydramine Dosage Calculator

Mild allergic itching, pre-trip motion sickness, vaccine-reaction prevention as advised by your vet, or short-term insect-bite relief.

The Cat Diphenhydramine Dosage Calculator is a quick reference, not a substitute for veterinary advice. Always cross-check with a vet, especially for medication or toxicity questions.

Frequently asked questions about Cat Diphenhydramine Dosage Calculator

Is Benadryl safe for cats?

Plain diphenhydramine is generally considered safe for short-term use, but always confirm with your vet.

How long does it take to work?

Onset is 30–60 minutes orally; effects last 4–8 hours.

Can I use the children's liquid?

Yes if it contains only diphenhydramine. Avoid products containing xylitol or alcohol.

What if my cat vomits the dose?

Wait at least an hour and call your vet before redosing.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.