The free PETHEALTH+ calculator estimates theobromine dose from your dog’s weight and the type and amount of chocolate eaten, then bands the risk. It uses average cocoa content — a rough triage guide only. Always phone your vet or Animal PoisonLine after any chocolate ingestion.
Chocolate toxicity calculator
Estimate whether your dog may have eaten a toxic dose of theobromine. This is a guide only — always phone your vet if your dog ate chocolate, even if the result looks low.
Based on published theobromine thresholds used in UK veterinary toxicology triage. Not a substitute for veterinary advice. Read our full chocolate poisoning guide.
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How much chocolate is toxic to a dog?
Approximate amount that reaches the dose where mild signs are expected (20 mg of theobromine per kg). Heart rhythm problems and tremors are expected at about double these amounts, and life-threatening signs at about three times. Products vary, so treat any amount as a reason to phone your vet.
Grams of chocolate reaching the mild-signs threshold, by dog weight
Chocolate
5 kg dog
10 kg dog
20 kg dog
30 kg dog
Milk chocolate
50 g
100 g
200 g
300 g
Dark chocolate (~50%)
18 g
36 g
73 g
110 g
Dark chocolate (70%+)
11 g
22 g
44 g
67 g
Cocoa powder / baking
6.7 g
13 g
27 g
40 g
For scale, a standard UK milk chocolate bar is about 45 g. Theobromine averages used: milk 2 mg/g, dark ~50% 5.5 mg/g, dark 70%+ 9 mg/g, baking 15 mg/g. White chocolate contains almost none but its fat and sugar can still cause pancreatitis.
How the calculator works
It multiplies the amount eaten by the average theobromine content of that chocolate type, divides by your dog’s weight, and compares the result with veterinary triage bands. Source: MSD Veterinary Manual, chocolate toxicosis table; ASPCA APCC figures as cited, cross-checked against UK VPIS guidance; figures reviewed 2026-07-17. Caffeine in chocolate adds to the effect and is not counted separately, which is one reason a “low” result still needs a phone call. Read the full chocolate poisoning guide or call Animal PoisonLine on 01202 509000.
Frequently Asked Questions
How accurate is the chocolate calculator?
It estimates theobromine dose using average cocoa content. Individual products vary — always phone your vet or Animal PoisonLine with the wrapper details.
What if the calculator says low risk?
Still call your vet. Small dogs, combined ingestion, or dark chocolate can be more dangerous than the estimate suggests.
How much milk chocolate is dangerous for a 10 kg dog?
Using average cocoa content, about 100 g of milk chocolate reaches the dose where mild signs such as vomiting and restlessness are expected (20 mg of theobromine per kg). Dark chocolate reaches it with far less — phone your vet whatever the amount.
What theobromine doses does the calculator use?
Mild signs from about 20 mg per kg of bodyweight, heart rhythm problems and tremors from about 40 mg per kg, and life-threatening signs such as seizures from about 60 mg per kg — veterinary triage bands, not a safe limit.
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When it can’t wait, call your vet. Breathing difficulty, collapse or suspected poisoning need urgent advice.