Grapes and raisins can cause acute kidney injury in dogs, and no toxic dose has ever been established for them. Tartaric acid has been proposed as the agent. For that reason this calculator does not split risk into dose bands. It only places the amount you enter side by side with the working figures that are used as a reason to call a veterinarian.
The working reference ASPCA toxicologists use is more than one grape or raisin per 10 pounds of body weight. The lowest amount at which signs have been reported is 0.3 ounces of grape per pound of body weight, about 18.8 grams per kilogram, while for concentrated raisins it is about 2.8 grams per kilogram, so the weight check asks which one was eaten. This tool converts both of those to the weight you entered. Figures current as of October 2026.
About 74 percent of animals that eat grapes are reported to show no signs, but there is no way to predict which animal goes on to kidney injury. That is why the conclusion here does not change when the amount falls under the reference. Cream of tartar is treated as an emergency at any measurable amount as well. 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
No toxic dose has been established and kidney injury has been reported at very small amounts. Call your veterinarian with the amount and the time.
The piece reference (one per 10 lb) applies to both, so count them together. The weight reference differs: raisins are concentrated, and signs are reported from about 2.8 g/kg of body weight, far less than the roughly 18.8 g/kg reported for grapes.
Many animals pass through with no signs, but kidney injury can take more than a day to show. Decide on watching at home together with your veterinarian.