Free tool
Dog Chocolate Toxicity Calculator NZ
If your dog has eaten chocolate, call your vet now— this calculator doesn't replace that call. It estimates the dose your dog has eaten in mg per kg of body weight and compares it with the thresholds in the Merck Veterinary Manual, so you can tell the vet exactly what happened.
Enter your dog's weight, the type of chocolate and how much they ate. If your dog is having a seizure, has collapsed or is struggling to breathe, skip this and go to a vet now.
What to do now
- Call your vet, or your nearest after-hours emergency vet. You can also call the NZ Animal Poisons Helpline on 0800 869 738 (charges apply).
- Don't try to make your dog vomit unless a vet tells you to. A vet can do it safely; vets usually consider it within about 2 hours of eating.
- Seizure, collapse or trouble breathing: go to a vet immediately.
- Keep the wrapper and note the time your dog ate it.
Signs usually start 6–12 hours after eating, so a dog that seems fine now may not stay fine. The National Poisons Centre (0800 764 766) is for people; it refers pet owners to their vet or the Animal Poisons Helpline.
How it works
Chocolate contains theobromine and caffeine, together called methylxanthines. Merck gives theobromine a half-life of about 17.5 hours in dogs, so it stays in the body a long time. The calculator multiplies the amount eaten by the methylxanthine content Merck lists for that type of chocolate, and divides by your dog's weight. For dark chocolate with a known cocoa percentage it scales from baking chocolate, as Merck does: a 70% bar is about 15.5 × 0.70 ≈ 10.9 mg per gram. Where Merck gives a range, the result is judged on the higher end.
Real chocolate varies by brand and recipe, and dogs vary in how they react. Treat the result as information to pass on to your vet, not as a reason to wait.
Keep reading
- Can Dogs Eat Chocolate? — the NZ guide
- Foods Dogs Can and Can't Eat — the NZ list
- Toxic Plant Checker NZ — is that plant dangerous to your pet?
Frequently asked questions
How much chocolate is toxic to a dog?
The Merck Veterinary Manual says mild signs may occur at 20 mg of methylxanthines (theobromine and caffeine) per kg of body weight, effects on the heart at 40–50 mg/kg, and seizures at 60 mg/kg or more. For a 10 kg dog, 20 mg/kg is reached with roughly 87 g of milk chocolate, 36 g of dark chocolate or 7 g of cocoa powder. Dogs vary, and Merck notes severe signs can occur at much lower doses, so call your vet whatever the amount.
Which type of chocolate is most dangerous for dogs?
The darker and more bitter, the more dangerous. Per gram, Merck lists cocoa powder at about 28.5 mg of methylxanthines, unsweetened baking chocolate 15.5 mg, cocoa bean hulls 9 mg, dark or semisweet chocolate 5.3–5.6 mg, milk chocolate 2.3 mg and white chocolate 0.04 mg.
How long after eating chocolate will a dog show signs?
Merck says signs usually start within 6–12 hours and can last up to 72 hours in severe cases. Don't wait for signs before calling: vets usually consider making a dog vomit within about 2 hours of eating, and early treatment reduces how severe the poisoning gets.
What are the signs of chocolate poisoning in dogs?
Early signs listed by Merck include drinking a lot, vomiting, diarrhoea, a swollen belly and restlessness. These can progress to hyperactivity, passing a lot of urine, wobbliness, stiffness, tremors and seizures.
Should I make my dog vomit after eating chocolate?
No, not unless a vet tells you to. The NZ National Poisons Centre's first-aid advice for pets is not to induce vomiting, and to call a vet or the NZ Animal Poisons Helpline instead. A vet can make your dog vomit safely with medication.
Who do I call in New Zealand if my dog eats chocolate?
Call your own vet, or your nearest after-hours emergency vet. You can also call the NZ Animal Poisons Helpline on 0800 869 738, which charges for calls. The National Poisons Centre (0800 764 766) handles human poisonings and says it is not expert in animal poisonings.
Is white chocolate safe for dogs?
It isn't a good idea. White chocolate has very little theobromine (Merck lists 0.04 mg per gram), but Merck notes the high fat in chocolate products can trigger pancreatitis in some dogs. Call your vet if your dog has eaten a lot.
Sources
- Merck Veterinary Manual — Chocolate Toxicosis in Animals (doses, methylxanthine content, signs, timing) — checked 9 November 2026
- National Poisons Centre (NZ) — Animal Helpline (who to call for animals) — checked 9 November 2026
- National Poisons Centre (NZ) — Pets get poisoned too (first aid: do not induce vomiting) — checked 9 November 2026
Important: this is general information, not veterinary advice. If your dog has eaten chocolate, call a NZ vet or the NZ Animal Poisons Helpline.