Free breeder tool
Heat cycle predictor
Enter the first day of her last heat. Add the one before it and the prediction uses her own interval instead of the breed average.
First day of last heat (YYYY-MM-DD or MM/DD/YYYY)
First day of the heat before that (optional)
Enter the last heat date to see the prediction.
How the prediction works
With one date, the calculator assumes the common 6.5-month interval (about 198 days). With two dates it measures her actual interval, which is a far better predictor because individual bitches tend to repeat their own rhythm. The window is ±14 days; start watching for swelling and discharge at the early end, and plan progesterone testing to begin about day 5 of proestrus.
How often do female dogs go into heat?
Most bitches cycle every 6–8 months. Some breeds (Basenji, some primitive breeds) cycle once a year, and small breeds can cycle more often. An individual bitch is usually consistent with herself, which is why her own previous interval is the best predictor.
When should progesterone testing start?
Around day 5–7 after the first signs of proestrus (swelling, bloody discharge), then every 2–3 days until the LH surge, then daily or every other day to catch ovulation.
How long does a heat last?
Proestrus and estrus together average about 2–3 weeks, with wide individual variation. The fertile window is only a few days within that, located by progesterone testing.
BreedBloom does this automatically for every litter: due-date window, ultrasound and X-ray reminders, temperature checks, and per-puppy weight curves.
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