Theobromine dose in mg/kg, mapped against veterinary severity thresholds
| Chocolate Type | mg per Ounce | mg per Gram | Danger Level |
|---|---|---|---|
| White chocolate | 0.09–0.35 | trace | Essentially none (fat/sugar upset only) |
| Milk chocolate | 44–58 | 1.6–2.0 | Moderate |
| Semisweet / dark | 135–160 | 4.8–5.6 | High |
| Unsweetened baking | 390–450 | 13.8–15.9 | Extreme |
| Cocoa powder | 400–737 | 14.1–26.0 | Extreme |
Published theobromine ranges as reported by the Merck Veterinary Manual and ASPCA Animal Poison Control; actual content varies by brand and cacao percentage. Darker usually means deadlier: the compound is concentrated in cocoa solids, so higher-percentage dark chocolate climbs toward baking-chocolate territory.
| Dose (mg/kg) | Severity | Typical Signs |
|---|---|---|
| Under 20 | Mild to none | Vomiting, diarrhea from fat and sugar |
| 20–40 | Moderate | Vomiting, restlessness, excessive thirst, pacing |
| 40–60 | Severe | Racing heart, muscle tremors, hyperactivity |
| Above 60 | Potentially lethal | Seizures, arrhythmias; the LD50 is estimated near 100–200 mg/kg |
Threshold bands consolidated from Merck Veterinary Manual and ASPCA APCC guidance. Individual sensitivity varies with age, health, and size; small dogs hit every threshold sooner because the same amount of chocolate divides into fewer kilograms.
| Dog Weight | Milk Chocolate to Reach 20 mg/kg | Baking Chocolate to Reach 20 mg/kg |
|---|---|---|
| 10 lb | ~1.8 oz | ~0.2 oz |
| 30 lb | ~5.3 oz | ~0.6 oz |
| 50 lb | ~8.9 oz | ~1.1 oz |
| 80 lb | ~14.2 oz | ~1.7 oz |
Ounces needed to cross the mild-signs threshold of 20 mg/kg, computed at typical theobromine values (51 mg/oz milk, 420 mg/oz baking). A single square of baking chocolate barely qualifies as a snack for you, but it crosses the line for a 10-lb dog.
Dogs metabolize theobromine, the stimulant in cocoa, far more slowly than humans do. It builds up, strains the heart, irritates the nervous system, and lingers for days. The math behind every chocolate-toxicity chart is the same: estimate how much theobromine went in, divide by the dog's body weight in kilograms, and read the dose against clinical thresholds.
Dose (mg/kg) = theobromine eaten (mg) ÷ dog weight (kg), where theobromine eaten = amount × the chocolate type's mg-per-ounce content. Since published theobromine content is a range, the calculator reports a dose range and uses the typical value to pick the severity band.
Enter your dog's weight in pounds or kilograms, pick the closest chocolate type, and estimate the amount eaten. Wrapper math helps: a standard milk chocolate bar is about 1.55 oz, a bag of dark chocolate chips 10–12 oz, one baking square half an ounce. When the type is unknown, run it once as milk and once as dark to see both ends of the range.
A 50-lb Labrador shares a 4-oz milk chocolate bar. Four ounces at 44–58 mg/oz delivers 176–232 mg of theobromine. At 22.7 kg, that's 7.8–10.2 mg/kg, below the 20 mg/kg threshold: expect, at worst, an evening of GI grumbling, and it would take nearly 8.9 oz of that same chocolate to reach the mild line.
Now the scary version. A 12-lb terrier eats 2 oz of dark chocolate. At 135–160 mg/oz that's 270–320 mg, and at 5.4 kg the dose is 49.6–58.8 mg/kg, squarely in the severe band where tremors and cardiac signs appear. And a 20-lb beagle swallowing 4 oz of baking chocolate takes on 172–198 mg/kg, near the estimated lethal range for theobromine, an emergency room trip, full stop.
One more honesty note: chocolate also contains caffeine, roughly a tenth of the theobromine by weight, which stacks its own stimulant effect on top. The calculator's numbers cover theobromine only, one more reason to let a vet make the final call.
It depends on the chocolate and the dog. The theobromine LD50 in dogs is estimated around 100-200 mg per kg of body weight. For a 20-lb dog that's roughly 2-5 oz of unsweetened baking chocolate (390-450 mg/oz) but 16-41 oz of milk chocolate (44-58 mg/oz). Serious symptoms can begin far below lethal doses, around 40-60 mg/kg, so don't wait for danger math to start making calls.
Watch closely and call your vet or a pet poison line anyway. Theobromine is slow to clear in dogs, and symptoms commonly take 6 to 12 hours to show, starting with vomiting, diarrhea, restlessness, and thirst. A dog that seems fine at hour two can be in trouble at hour eight. Have the wrapper and amount handy when you call.
Practically no. White chocolate carries only trace theobromine, about 0.25 mg per ounce, so a 10-lb dog would need to eat over 350 oz to approach the mild threshold. The real issues with white chocolate are its fat and sugar, which can trigger pancreatitis or GI upset in a serious binge.
Typically 6 to 12 hours, since dogs metabolize theobromine very slowly. Early signs include vomiting, diarrhea, increased thirst, restlessness, and pacing. Higher doses progress to a racing heart, muscle tremors, and seizures. Symptoms can linger for days because of the slow clearance, which is part of why vets take even moderate doses seriously.
Not on your own initiative. Inducing vomiting is sometimes the right move, but the timing, method, and whether it's safe depend on the dog and the dose, and doing it wrong causes its own injuries. Call your vet or ASPCA Animal Poison Control at (888) 426-4435 first and follow their instructions; they may tell you to come in for activated charcoal or monitoring instead.