Dog Heat Cycle Tracker & Next Season Predictor
Track your un-spayed female dog's heat (estrus) cycles, predict future heat dates, and identify fertile mating windows.
Dog Heat Cycle & Fertile Window Tracker
How to Use the Dog Heat Cycle Tracker & Next Season Predictor
- Enter the start date of last known heat cycle.
- Select breed size (Small dogs cycle every 4-6 months, Large dogs every 6-8 months, Giant breeds every 12-18 months).
- View predicted next heat start date and fertile standing estrus phase window.
Clinical Methodology & Formula Breakdown
Calculates the 4 distinct phases of the canine estrous cycle (Proestrus 9d, Estrus 9d, Diestrus 60d, Anestrus 4-5m) based on average cycle interval for breed weight class.
- Theriogenology Canine Reproductive Guidelines
- AKC Female Dog Health
Worked Clinical Example
The 4 Phases of the Canine Estrus Cycle
| Phase Name | Typical Duration | Physical Signs | Fertility Status |
|---|---|---|---|
| 1. Proestrus | 7 - 10 Days | Swollen vulva, bloody discharge | Not Fertile (Attracts males, rejects mating) |
| 2. Estrus | 5 - 9 Days | Straw-colored discharge, tail flagging | HIGHLY FERTILE (Ovulation phase) |
| 3. Diestrus | 60 - 70 Days | Vulva swelling subsides | Not Fertile (Progesterone dominant phase) |
| 4. Anestrus | 4 - 5 Months | Uterine repair phase | Sexual Inactivity |
Frequently Asked Questions
At what age do female dogs have their first heat?
Small breeds may have their first heat at 6 months, while large and giant breeds may not have their first heat until 12 to 24 months.
How long does a dog heat cycle last total?
The active bleeding and fertile phase lasts 2 to 3 weeks (typically 18 to 21 days).
What is "tail flagging"?
When a female dog enters fertile estrus, she will deflect her tail to one side when touched on her lower back to signal readiness for mating.
Can a dog get pregnant on her first heat cycle?
Yes! Female dogs are sexually capable of pregnancy on their very first heat, though breeding on the first heat is discouraged by veterinarians.
What is Pyometra?
Pyometra is a severe, life-threatening bacterial uterine infection occurring 2-8 weeks following a heat cycle in unspayed females. It requires emergency surgery.