Dog Melatonin Dosage Calculator
Enter your dog's weight for a typical melatonin dose used for anxiety, noise phobia and sleep — and read the xylitol warning before you give any.
Estimate only — not veterinary advice. Every animal is different; for a medication dose, a possible poisoning, or any emergency, call your veterinarian or an animal poison control line right away.
How the dose is worked out
Melatonin is dosed in fixed steps by body-weight band rather than a strict per-kilogram formula, usually given up to every 8–12 hours. The calculator picks the typical band for your dog's weight. Because it's a calming supplement, it's reasonable to start at the lower end and see how your dog responds — with your vet's okay.
The one thing that really matters: xylitol
Many melatonin gummies and flavored liquids contain xylitol, a sweetener that is toxic to dogs even in small amounts. Always read the ingredient list and choose a plain tablet or capsule with no xylitol and no extra active ingredients. If your dog ate a xylitol-containing product, check the xylitol toxicity calculator right away.
Frequently asked questions
- How much melatonin can I give my dog?
- A common rule of thumb by weight: about 1 mg for dogs under 10 lb, 1.5 mg for 10–25 lb, 3 mg for 26–100 lb, and 3–6 mg for dogs over 100 lb, given up to every 8–12 hours. Start at the low end and confirm the dose and timing with your vet, especially the first time.
- Is melatonin safe for dogs?
- Plain melatonin is generally well tolerated and is widely used for anxiety and sleep. The main risks are drowsiness, and — importantly — xylitol, which is in many melatonin gummies and is toxic to dogs. Use a plain tablet or capsule with no xylitol, sweeteners or added ingredients.
- What is melatonin used for in dogs?
- Most often for anxiety and fear — fireworks, thunderstorms, separation, vet visits — and to help with sleep or nighttime restlessness in older dogs. Vets also sometimes use it for certain types of hair loss. It's a calming aid, not a treatment for a medical emergency.
- When should I avoid melatonin or ask the vet first?
- Check with your vet before using it in puppies, pregnant or nursing dogs, diabetic dogs (it can affect blood sugar), or any dog on other sedatives or medicines. And never use a product that contains xylitol or is a 'PM' combination with pain relievers.
Sources
These are the references behind this calculator. Where a source gives a range we take the midpoint and round toward caution, and where we go beyond what a source states — an extra safety margin, or a rule of thumb rather than a clinical threshold — the page says so in the text above.