Chocolate poisons dogs because they clear theobromine, a stimulant related to caffeine, far more slowly than people do. The danger depends on three things: how much theobromine the chocolate contains (darker is worse), how much was eaten, and how big the dog is. This calculator combines them into a dose per kilogram, the number vets use to decide what to do, and tells you what that dose means.
How it is calculated
- Theobromine = grams of chocolate × the content for that type: milk chocolate about 2 mg/g, dark 5–8, baker’s 14, cocoa powder 20. White chocolate has almost none.
- Caffeine is added, since it acts the same way; it is a smaller contribution.
- Dose = total milligrams ÷ dog’s weight in kg.
- Severity bands: under 20 mg/kg usually mild; 20–40 moderate; 40–60 cardiac effects; over 60 seizures possible; 100–200 mg/kg can be fatal.
Example
A 15 kg dog eats a 100 g bar of milk chocolate: about 200 mg theobromine plus 20 mg caffeine, so 14.7 mg/kg. Mild signs are possible; most dogs this size are fine with monitoring. The same 100 g of 70% dark chocolate gives 800 mg theobromine, 59 mg/kg, a serious emergency. And 100 g of baker’s chocolate would be 100 mg/kg, potentially fatal.
What happens and when
Signs usually start 6 to 12 hours after eating: vomiting, diarrhoea, restlessness, drinking and urinating more, panting and a racing heart. Larger doses bring tremors, arrhythmias, seizures and collapse. Theobromine has a half-life of about 17 hours in dogs, so symptoms can last three days. Treatment in the first two hours, inducing vomiting and giving activated charcoal, is far more effective than treating symptoms later, which is why the advice is to call before signs appear.
Limits of the estimate
Theobromine content varies by brand, especially in dark chocolate. Fat and sugar in large amounts can cause pancreatitis regardless of theobromine. Small, old or sick dogs are more sensitive. If in doubt, treat the dose as one band higher and call.
Frequently asked questions
How much chocolate is toxic to a dog?
Symptoms begin around 20 mg of theobromine per kg of body weight. For a 10 kg dog that is about 100 g of milk chocolate, 25–40 g of dark chocolate, or 15 g of baker’s chocolate. Enter your dog’s weight above for exact amounts.
My dog ate chocolate but seems fine. Should I worry?
Symptoms take 6–12 hours to appear, so "seems fine" right after eating means nothing. Use the calculator; if the dose is above 20 mg/kg, call a vet now while inducing vomiting still helps.
Can I make my dog vomit at home?
Only on a vet’s instruction. 3% hydrogen peroxide is sometimes advised by phone at a specific dose; the wrong dose or the wrong product can cause serious damage. Call first.
Is white chocolate dangerous?
Not from theobromine, which it barely contains. The fat and sugar can still upset the stomach or trigger pancreatitis in large amounts.
How long does chocolate poisoning last?
Up to 72 hours, because theobromine is eliminated slowly. Dogs treated early usually recover fully within a day or two.
Sources
- Merck Veterinary Manual: Chocolate Toxicosis in Animals
- ASPCA Animal Poison Control Center: Chocolate
- VCA Animal Hospitals: Chocolate Poisoning in Dogs
By Calcelate Team. Formula from the sources above.
- 2026-09-14 · Formula and texts checked
- 2026-09-14 · Reference data as of this date
- 2026-09-14 · Emergency numbers verified against official sources