What hurts a dog in chocolate is theobromine plus caffeine, together called methylxanthines. Enter the body weight, the amount eaten and the chocolate type, and this calculator estimates how many milligrams of methylxanthine the dog took in per kilogram of body weight and lines that up with the thresholds reported in the literature. If the wrapper lists the content, entering it yourself is far more accurate.
The literature broadly agrees on 20 mg per kilogram as the point where mild signs such as restlessness and vomiting appear, 40 to 50 mg/kg for cardiac effects such as a racing heart and tremors, and 60 mg/kg for seizures. Theobromine content runs about 595 mg per ounce in cocoa powder, over 400 mg/oz in dark and baking chocolate and 40 to 60 mg/oz in milk chocolate, and the product spread is wide, so this tool applies the high end for milk and dark chocolate and a typical value for cocoa powder, which can run higher in some products. These thresholds come from what veterinary toxicology sources state in common rather than a single named guideline document, written as of October 2026.
Lethal-dose numbers vary so much between sources that this tool does not use them. Severe and fatal cases are reported well below those figures and individual response varies widely. White chocolate carries only trace methylxanthine, so no threshold is applied to it, and no band here is ever reported as a level that is fine to eat. This tool is for reference only and does not replace veterinary care. Contact your veterinarian right away if you notice symptoms or suspect a problem.
Frequently Asked Questions
Methylxanthine signs usually show up hours later. Even with a low estimate, call your veterinarian with the fact of the exposure and the amount.
Assume the darkest type for the estimate, then tell your veterinarian plainly that the type is unknown.
Sources disagree widely and severe cases occur well below those numbers, so treating a lethal dose as the yardstick delays the response.