PawslyDog heat cycle calculator
Enter the first day of bleeding of the last heat: we tell you which day it is, the indicative window and when the next one is expected. It is an estimate from the calendar, not a fertility test: every dog is different.
Pick the start date of the last heat to see the dates.
Informational tool: not a fertility test and not a replacement for your vet. For decisions about breeding, litters or spaying, ask your vet.
The heat phases at a glance
These are averages: they vary a lot with breed, size and age.
| Phase | Average length | What you see |
|---|---|---|
| Proestrus | about 9 days | Bleeding and a swollen vulva; males are interested but she does not accept them. |
| Estrus | about 9 days | Discharge gets lighter; this is when she may accept a male. |
| Diestrus | about 2 months | End of the heat; possible pregnancy or, in some dogs, a false pregnancy. |
| Anestrus | a few months | Rest, until the next heat. |
A heat lasts about three weeks on average and usually repeats about every 6 months: some dogs (especially small ones) more often, others once a year.
Dog heat FAQ
How often does a female dog go into heat?
On average about twice a year, roughly every 6 months. It varies with breed and size: some small dogs every 4 months, others only once a year. Logging heats makes the estimate more accurate.
How long does a heat last?
About three weeks on average, but it can be shorter or longer. It is over when the bleeding stops, the vulva goes down and she refuses males.
When is the first heat?
Usually between 6 and 24 months: earlier in small dogs, later in large ones. The first heat can be irregular.
Which days are fertile?
The calendar can only give a wide estimate: roughly the second week, between day 9 and day 14. To really know you need tests (progesterone, cytology) done by a vet. If you want to avoid a litter, keep her away from males for the whole heat.
Is the next heat date exact?
No, it is an estimate: the heat can come earlier or later. The more heats you log, the closer the forecast gets to your dog.
When should I call the vet?
If you see abnormal or smelly discharge, illness, fever, a very long heat or one that has not come for a long time. For breeding, litters or spaying always ask your vet.
How do I get a reminder?
Download the .ics file and open it in your calendar: it adds the expected heats with an alert two weeks ahead. Or use Pawsly, which reminds you 14 days before and keeps the record.
General guidance inspired by the Merck Veterinary Manual and Cornell University College of Veterinary Medicine. Averages: every dog is different.
Also for vaccines: Vaccine schedule by age
Keep the heat record in the app
Pawsly remembers the expected heat, daily notes and vaccines too.