Dog chocolate toxicity calculator

How much chocolate is toxic to a dog?

Chocolate contains two stimulants, theobromine and caffeine, from a family of chemicals called methylxanthines. Dogs are sensitive to both, and theobromine stays in their bodies for a long time. Vets measure the danger as milligrams of the two together per kilogram of body weight. The Merck Veterinary Manual, written by a vet at the ASPCA Animal Poison Control Center, gives these levels:

• 20 mg/kg: mild signs such as vomiting, diarrhea and drinking more than usual.
• 40 to 50 mg/kg: effects on the heart, such as a racing or irregular heartbeat.
• 60 mg/kg and above: tremors and seizures.
• 100 to 200 mg/kg: the range in which half of dogs would be expected to die (the LD50).

These are general figures, not exact cut-offs. Dogs vary, and chocolate's fat can trigger pancreatitis on its own, which is why the calculator never tells you an amount is safe to ignore.

Which chocolate is most dangerous?

The darker and less sweet the chocolate, the more theobromine it holds. Cocoa powder has over ten times as much as milk chocolate, gram for gram. These are the figures the calculator uses:

Merck doesn't list high-cocoa dark bars separately, so for 60 to 69% and 70 to 85% chocolate we use USDA lab values. If your bar shows a cocoa percentage, pick the matching row; if it just says “dark”, choose the 70 to 85% option to be on the cautious side.

Chocolate toxicity chart by dog weight

The amount of each chocolate, in ounces, that reaches 20 mg/kg, the dose where mild signs begin. Smaller amounts can still cause an upset stomach, and three times these amounts reach the seizure range.

The pattern is the useful part: a 20 lb dog can get sick from about 2.8 oz of milk chocolate, but from only 0.41 oz of baking chocolate or 0.22 oz (6 g) of cocoa powder.

Symptoms of chocolate poisoning and when they start

Signs usually appear 6 to 12 hours after eating. Early on you may see thirst, vomiting, diarrhea, a swollen belly and restlessness. As the dose rises, dogs become hyperactive, pant, shake and pass more urine, and the heart can race or beat irregularly. High doses cause tremors, seizures and, in the worst cases, death. Because dogs clear theobromine slowly, severe cases can last up to 72 hours, and a dog that looks fine at bedtime can be worse by morning.

What to do if your dog ate chocolate

1. Move your dog away from any chocolate that's left and keep the wrapper or bag.
2. Work out the most your dog could have eaten and enter it above.
3. Call your vet, an emergency clinic, or a poison hotline: ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661. Both may charge a fee.
4. Don't give anything by mouth unless you're told to. If a vet asks you to make your dog vomit at home, the hydrogen peroxide dose calculator shows the amount and when never to try it.

At the clinic, vets usually make the dog vomit if the chocolate was eaten within about 2 hours and the dog is still acting normally. Dogs that already have signs are treated for them: heart monitoring, correcting blood salts and body temperature, and activated charcoal after very large doses. Vets may also keep the bladder empty, because theobromine can be reabsorbed from urine.

How the calculator works

dose (mg/kg) = grams eaten × mg per gram ÷ dog's weight in kg

Worked example: a 20 lb (9.1 kg) dog eats a 3.5 oz (99 g) bar of 70 to 85% dark chocolate. That bar holds about 873 mg of theobromine and caffeine, so the dose is 96 mg/kg: in the seizure range, and a reason to leave for the vet straight away. The same dog would need about 13.4 oz of milk chocolate to reach that dose.

The calculator adds theobromine and caffeine together, as vets do, and splits the total using USDA ratios so you can see each one. Checking other kitchen finds? Our is it toxic to dogs checker covers grapes, xylitol, onions and many more, and the xylitol calculator handles sugar-free sweets.