Dog heat calculator
Where is your dog today? Enter the first day of bleeding and see her stage, most fertile days, watch periods and the next heat at a glance.
A free calculator from Lunella, the app for tracking your dog’s heat day by day. For iPhone and Android.
Your dog's size
months
Enter a date and the result appears here.
How the calculator works
- Proestrus lasts about 9 days from the first day of bleeding, standing heat another 9 days. A heat takes about 18 days in total, 2 to 4 weeks in some dogs.
- Ovulation happens around day 11 on average. The eggs can be fertilised 2 to 4 days later, so around days 13 to 15. The popular rule of thumb "days 10 to 13" fits fewer than half of all dogs.
- Diestrus lasts about 63 days. Pyometra, a dangerous uterine infection, is most common 2 to 8 weeks after the heat; false pregnancy shows in weeks 6 to 9.
- The time to the next heat depends on size: small about 6 months, medium 7, large 7½, giant 10. If you know your dog's interval, the calculator uses it. We allow ±3 weeks.
- All values are reference values from the MSD Veterinary Manual, Cornell Riney Canine Health Center and dvm360. Your entries stay in your browser; nothing is sent.
