Dog Heat Cycle (Estrous) Calculator

Predict estrous cycle stages (Proestrus, Estrus, Diestrus, Anestrus), fertile mating windows, and expected due dates for female canines.

🐕 Pets

Verified Formula

Enter Calculation Inputs

Fill in the fields below. Instant client-side computation runs automatically in your browser as you type.

✓ Computed Output

Computation Ready

Calculation performed instantly via mantranews24 verified mathematical model.

Common Searches & Natural Queries

🔍 dog heat cycle calculator ovulation dates 🔍 canine proestrus estrus fertile window calculator 🔍 when is my dog fertile during heat 🔍 dog gestation and whelping date predictor 🔍 dog breeding cycle calculator

What is the Dog Heat Cycle?

The canine estrous cycle consists of four distinct physiological phases: Proestrus (swelling and bloody discharge, non-receptive), Estrus (standing heat, fertile receptive period lasting 5–9 days), Diestrus (luteal phase), and Anestrus (reproductive rest period lasting 4–5 months).

Mathematical Formula & Methodology

The mathematical model underlying this tool operates on the following verified equation:

Proestrus: Days 1–9; Estrus (Fertile Window): Days 9–14; Ovulation: Approx Day 11–12; Gestation: 63 days from ovulation

Understanding the Parameters:

First Day of Bleeding / Swelling — Primary input variable.
Average Cycle Interval (measured in months) — Primary input variable.

How to Use This Calculator

Select the date when initial vulvar swelling or bloody discharge was observed. The calculator generates a full calendar timeline of fertile mating dates, cycle conclusion, and the anticipated next heat.

Worked Numerical Example

💡

Heat begins October 1st: Proestrus runs Oct 1 to Oct 9. Estrus (fertile standing heat) begins Oct 10 and peaks Oct 11–14 (optimal breeding days). If bred on Oct 12, the expected whelping delivery date is approximately December 14 (63-day gestation). Next heat cycle anticipated in April.

Key Considerations & Standards

Small breeds often cycle every 4 to 6 months, while giant breeds like Great Danes or Mastiffs may only experience estrus every 12 to 18 months.

Frequently Asked Questions

When is a female dog most fertile?

Most female dogs ovulate around Day 11 to 13 of their cycle. The ova require an additional 48 hours to mature, making Days 12 through 15 peak fertility days.

How can a breeder know exact ovulation days?

Serum progesterone testing is the most reliable method. Progesterone reaches 2.0 ng/mL at the LH surge and 4.0–10.0 ng/mL during ovulation.