Cat ate chocolate? Set their weight, pick the chocolate and slide the amount eaten. The meter shows the theobromine dose, the risk level and what to do next.
✅ Free, instant, no signup · pounds & ounces (or kg & g) · Updated October 2026
What matters is the dose of theobromine per kilogram of body weight, not the chocolate alone. Cats begin to show signs around 20 mg/kg; serious heart effects appear from about 40 mg/kg and seizures around 60 mg/kg. The table shows how much of each chocolate reaches the 20 mg/kg threshold for common cat weights.
| Chocolate type | 5 lb cat | 8 lb cat | 10 lb cat | 12 lb cat | 15 lb cat |
|---|---|---|---|---|---|
| White chocolate | 2+ lb | 3.2+ lb | 4+ lb | 4.8+ lb | 6+ lb |
| Milk chocolate | 0.7 oz | 1.1 oz | 1.4 oz | 1.7 oz | 2.1 oz |
| Dark / semisweet | 0.29 oz | 0.46 oz | 0.57 oz | 0.69 oz | 0.86 oz |
| Extra-dark (70%+) | 0.2 oz | 0.32 oz | 0.4 oz | 0.48 oz | 0.6 oz |
| Baking chocolate | 0.1 oz | 0.16 oz | 0.2 oz | 0.24 oz | 0.3 oz |
| Cocoa powder | 0.06 oz | 0.09 oz | 0.11 oz | 0.14 oz | 0.17 oz |
Theobromine levels are averages from the Merck Veterinary Manual and vary by brand and cocoa percentage. Cocoa-powder and baking-chocolate amounts are tiny, so treat them as the highest risk. Higher cocoa percentage always means more theobromine.
Dose (mg/kg) = ounces eaten × 28.35 × theobromine mg per gram ÷ cat’s weight in kg. The calculator does this for you, including lb to kg conversion. Then it compares the result with these bands:
Low risk. Monitor at home for 24 hours and call if anything looks off.
Mild to moderate. Vomiting and restlessness are likely, so call your vet today.
Serious. Heart rhythm and tremor risk, so see a vet now.
Emergency. Seizures and heart failure are possible, so go immediately.
Take away what is left. Keep the wrapper: type, cocoa percentage, amount missing and time eaten are what your vet will ask first.
Use the calculator above. If you are unsure how much was eaten, assume the larger amount.
Call your veterinarian, an emergency clinic, or Pet Poison Helpline (855-764-7661) or ASPCA Animal Poison Control (888-426-4435). Both lines charge a consultation fee.
Hydrogen peroxide and salt can seriously harm cats. If decontamination helps, your vet will do it safely, ideally within about two hours.
Vomiting, diarrhea, drinking more, restlessness, pacing and a swollen or uncomfortable belly.
Panting or fast breathing, racing heartbeat, hyperactivity, muscle twitching and frequent urination.
Tremors, irregular heartbeat, seizures, weakness, collapse or coma. This is an emergency.
Signs usually appear within 6 to 12 hours but can be quicker, and they can last up to 72 hours. Cats hide illness, so subtle changes matter. See our full list of cat emergency symptoms.
The most dangerous everyday chocolate: about 5.6 mg/g for semisweet and 8 mg/g or more for 70%+. A bite can matter for a small cat. Calculate right away.
About 2.3 mg/g. A lick is usually fine; a whole bar can reach the toxic range for a small cat.
Almost no theobromine, so poisoning is unlikely. Fat and sugar can still upset the stomach and trigger pancreatitis.
CatVetFinder helps you find cat-friendly veterinary clinics near you, including those with emergency hours. Search by city, then call ahead so the team can prepare.
Cats can show signs of chocolate poisoning at about 20 mg of theobromine per kg of body weight, and serious heart and nerve signs appear from 40 mg/kg upward. For a 10 lb cat that is roughly 0.6 oz of dark chocolate, 1.4 oz of milk chocolate, or 0.2 oz of baking chocolate. Use the calculator above to check your cat’s exact weight and the exact amount eaten.
Stay calm, remove any remaining chocolate and note the type, amount and time. Enter those details and your cat’s weight into the calculator. If the dose is 20 mg/kg or higher, or your cat shows any symptom, call your vet, an emergency clinic or Pet Poison Helpline (855-764-7661) right away. Do not try to make your cat vomit at home.
Yes, although it is uncommon because cats rarely eat large amounts. Theobromine overstimulates the heart and nervous system, and large doses of dark, baking or cocoa-powder products can cause dangerous heart rhythms and seizures. Prompt veterinary treatment greatly improves the outcome, so do not wait to see whether symptoms appear.
Common signs are vomiting, diarrhea, increased thirst, restlessness, panting or fast breathing and a racing heartbeat. In more serious cases cats develop muscle tremors, an irregular heart rhythm, seizures and collapse. Signs usually start within 6 to 12 hours, sometimes sooner, and cats often hide how sick they feel.
Milk chocolate has about 2.3 mg of theobromine per gram, less than half the level in semisweet dark chocolate. A lick or one small piece is usually below the toxic dose for an adult cat, but a whole bar can be dangerous for a small one. Enter the amount into the calculator, and call a vet if the result is 20 mg/kg or more or if your cat is unwell.
It can be. Dark chocolate holds 2 to 3 times more theobromine than milk chocolate, so a little over half an ounce (about one small square) can reach the toxic range for an average 10 lb cat. Calculate the dose now, then call your vet or an emergency clinic if it reaches 20 mg/kg or higher. Early treatment, within about two hours of eating, works best.
White chocolate contains almost no theobromine, so it rarely causes chocolate poisoning. It is still high in fat and sugar and can cause vomiting or diarrhea, and it can trigger pancreatitis. Check the label too: products such as brownies, cookies or candy with white-chocolate chips can contain cocoa, xylitol, nuts or raisins.
Theobromine leaves a cat’s body slowly, so signs can last 24 to 72 hours without treatment. With veterinary care, most cats are monitored for a day or two while the toxin clears. Your vet will tell you how long to watch your cat at home afterward.
Treatment depends on the dose and timing. If your cat ate chocolate recently, a vet may induce vomiting and give activated charcoal to limit absorption, then provide IV fluids, heart monitoring and medication for tremors or seizures. Cats should never be made to vomit at home.
Sources: Merck Veterinary Manual (chocolate toxicosis), ASPCA Animal Poison Control and Pet Poison Helpline. This page is educational and does not replace advice from a licensed veterinarian.
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