How the Dog Heat Cycle Calculator works
Methodology
Next-cycle estimate = last start date + user-entered cycle length. The displayed fertile window is a rough observation window only.
Frequently asked questions
How often do dogs come into heat?+
Many cycle roughly twice a year, but breed, age and individual variation can make intervals shorter or much longer.
Important veterinary note
Calculator outputs are estimates for education and planning. They do not diagnose disease, replace a physical examination, or override advice from a veterinarian who knows your dog.