Calculate your dog's next heat cycle and fertile days
Calculate your female dog's next heat cycle
This calculator helps predict your female dog's next heat cycle. The average cycle is 6 months (can vary between 5-7 months).
Enter the first day of the last heat
Note: This is an estimate based on the average cycle. Individual cycles may differ. For breeding plans, consult a veterinarian and consider progesterone testing.
Most female dogs go into heat twice per year, every 6-8 months. Small breeds may cycle every 4-5 months, while very large breeds (e.g., Great Dane) sometimes only once a year. The first heat occurs between 6 and 24 months of age.
The entire heat cycle lasts about 21 days (3 weeks). Proestrus lasts 7-10 days with bloody discharge. Estrus lasts 5-9 days when the female is receptive to mating. Metestrus follows with 9-12 weeks of hormonal decline.
Ideally 2-3 months after the heat, when hormone levels are lowest. Spaying during heat increases bleeding risk. Discuss the optimal timing with your veterinarian.