What this calculator does
If your dog has eaten chocolate, call a vet or an animal poison line now rather than working through this page first. This calculator estimates a dose, which is useful information to have ready when you call, but it is not a substitute for advice and it cannot see your dog.
The toxic agent is theobromine, and how much of it is present varies enormously by chocolate type. Unsweetened baking chocolate carries around 450 mg per ounce, dark chocolate about 150, milk chocolate about 50, and white chocolate a negligible quarter of a milligram. The same weight of baking chocolate is therefore roughly nine times the dose of milk chocolate.
The formula
The theobromine content per ounce for the chocolate type is multiplied by the ounces eaten, then divided by body weight in kilograms to give a dose in mg per kg. That dose is compared against published veterinary thresholds: roughly 20 mg/kg for mild signs, 40 to 50 for cardiac effects, and 60 and above for potential seizures. These are guides, and individual dogs vary.
| Term | Meaning |
|---|---|
| Theobromine | The stimulant in cocoa that dogs metabolise slowly, which is what makes chocolate dangerous to them. |
| mg/kg | Milligrams of theobromine per kilogram of body weight, the dose that determines risk. |
| 20 mg/kg | The threshold around which mild signs such as vomiting and restlessness typically begin. |
| 60 mg/kg | The level above which seizures become a real possibility. Treat as an emergency. |
The inputs explained
| Field | What to enter |
|---|---|
| Chocolate type | The type of chocolate. This matters more than the amount, because theobromine content varies by a factor of nearly a thousand across the range. |
| Amount eaten (oz) | How much was eaten, in ounces. If unsure, estimate high rather than low. |
| Dog's weight (kg) | The dog body weight in kilograms. Small dogs reach dangerous doses from very small amounts. |
When to use it
Having useful information ready for the vet
A vet will want to know the type of chocolate, roughly how much, and the dog weight. Working the dose out while you are on the phone saves time at the point where time matters.
Understanding why type matters so much
A square of milk chocolate and a square of baking chocolate are not remotely comparable, and seeing the doses side by side makes the difference concrete.
Judging risk for a small dog
Body weight is a divisor, so the same biscuit is a very different dose for a 4 kg terrier than for a 40 kg retriever.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How does chocolate type change the dose?
The same 2 ounces eaten by the same 15 kg dog, across the four chocolate types.
| Chocolate type | Theobromine dose | Total theobromine eaten | Risk level |
|---|---|---|---|
| Unsweetened baking | 60.0 mg/kg body weight | 900 mg | Severe risk (potential for seizures): treat as an emergency |
| Dark / semi-sweet | 20.0 mg/kg body weight | 300 mg | Mild signs possible (vomiting, restlessness) |
| Milk | 6.7 mg/kg body weight | 100 mg | Below typical mild-toxicity threshold |
| White | 0.0 mg/kg body weight | 1 mg | Below typical mild-toxicity threshold |
How much dark chocolate reaches each risk level?
Increasing amounts of dark chocolate eaten by the same 15 kg dog.
| Amount eaten | Theobromine dose | Risk level | Total theobromine eaten |
|---|---|---|---|
| 1 oz | 10.0 mg/kg body weight | Below typical mild-toxicity threshold | 150 mg |
| 2 oz | 20.0 mg/kg body weight | Mild signs possible (vomiting, restlessness) | 300 mg |
| 4 oz | 40.0 mg/kg body weight | Moderate–severe risk (cardiac symptoms possible) | 600 mg |
| 8 oz | 80.0 mg/kg body weight | Severe risk (potential for seizures): treat as an emergency | 1,200 mg |
Questions
My dog ate chocolate. What should I do?
Contact a vet or an animal poison line straight away, even if the calculated dose looks low. They may advise inducing vomiting, which is time-sensitive and should only be done on veterinary instruction. Have the chocolate type, the amount and your dog weight ready.
Why is chocolate poisonous to dogs but not people?
Because dogs metabolise theobromine far more slowly. A human clears it in a few hours; a dog takes about 17 hours to clear half of it, so it accumulates to levels that affect the heart and nervous system. Cats are similarly affected but rarely eat chocolate voluntarily.
How long do symptoms take to appear?
Typically 2 to 4 hours for the first signs, though they can take up to 12. Vomiting, restlessness and increased thirst come first, then racing heart rate and tremors at higher doses. Waiting to see whether symptoms appear is not the right approach: call before they do.
Is white chocolate safe?
It contains almost no theobromine, so theobromine poisoning is not the concern. It is still a large quantity of fat and sugar, which can cause stomach upset and, in susceptible dogs, pancreatitis. Not toxic in the same way does not mean harmless.
For onion and garlic toxicity, see the dog onion toxicity calculator. For daily calorie needs, see the dog and cat calorie calculator.