Calculator
Best time to breed a dog
Updated October 2026 · Information only, not veterinary advice
Step 1
First day of bleeding
Day 1 is the first day you notice a swollen vulva or bloody discharge. The dates below are typical, not exact. Her real ovulation day needs a progesterone test.
Typical mating window
Oct 17 to Oct 22, 2026
Today is day 7 of her season. If she conceives in the typical window, the expected due date is Dec 17 to Dec 22, 2026.
| Step | Dates | Note |
|---|---|---|
| Start progesterone tests | From Oct 11 (day 5 to 7) | Your vet repeats the test every 1 to 2 days until it shows ovulation |
| Typical ovulation | Oct 15 to Oct 20 (day 9 to 14) | Can be as early as day 5 or as late as day 20 or more |
| Typical mating days | Oct 17 to Oct 22 (day 11 to 16) | A few days after ovulation, set by progesterone |
Dogs vary a lot. Counting days alone misses the fertile window in many bitches. Use progesterone testing to time mating, and then use the due date calculator with the confirmed ovulation date.
Why counting days is not enough
Ovulation in dogs can happen anywhere from about day 5 to day 20 of the season, and the same dog can vary between cycles. A fixed schedule will miss the window for many dogs. Progesterone rises in a predictable way around ovulation, which is why vets use blood tests to place the breeding days.
| Progesterone (ng/mL) | What it usually means |
|---|---|
| Under 2 | Not close to ovulation yet. Test again in 1 to 2 days |
| About 2 to 5 | LH surge has happened. Ovulation is around the corner |
| About 5 to 8 | Ovulation has occurred |
| About 8 to 15+ | Eggs are mature and fertile. Typical mating days |
After mating
Once you have the ovulation date, use the due date from ovulation calculator for a two-day window, and book the scans with the ultrasound and X-ray planner.
See your vet before breeding if…
- She has not had a health check, vaccine review and breed-relevant genetic tests.
- Her seasons are irregular, very short or very long, or you have never seen one.
- She is under two years old, over six, or has had trouble in a past pregnancy or whelping.
Questions
Frequently asked questions
What day of her heat should I breed my dog?
On average, ovulation falls around day 9 to 14 after bleeding starts, and mating a few days after ovulation works best. But the range is wide, from about day 5 to day 20 or later, so progesterone testing is the reliable way to find her day.
When does a dog stop bleeding in heat?
Bleeding often lightens or stops around the time she is fertile, but some dogs bleed throughout. Do not rely on the color or amount of discharge to time breeding.
How do I know when my dog is ready to breed?
She will usually stand still, flag her tail to one side and accept the male. A progesterone blood test confirms the timing and is much more accurate than behavior alone.
How many days is a dog fertile?
The eggs are ready to be fertilized for about two to three days after they mature, and sperm can live several days inside her. In practice the fertile window is roughly a week, with the best days a few days after ovulation.
Can a dog get pregnant if she is not bleeding?
Yes. Many dogs are most fertile when the discharge has faded to pale pink or clear. Only the standing and ovulation tests tell you.
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