Dog Heat Cycle Calculator

Understanding Heat Cycles

Key Facts:

  • First heat: Usually between 6-12 months
  • Cycle length: Typically every 6-8 months
  • Heat duration: 2-4 weeks total
  • Fertile period: Days 9-14 typically

Heat Cycle Stages

Proestrus (9 days)

  • Swollen vulva
  • Bloody discharge
  • Male attraction begins
  • Not receptive to males

Estrus (9 days)

  • Discharge lightens
  • Receptive to males
  • Ovulation occurs
  • Fertile period

Diestrus (60-90 days)

  • No longer receptive
  • Discharge stops
  • Pregnancy or rest phase
  • Hormonal changes

Anestrus (3-4 months)

  • Sexual inactivity
  • Reproductive rest
  • Hormone levels low
  • Body prepares for next cycle
Breed Size Average Cycle Length First Heat Age
Small Breeds 6 months 6-8 months
Medium Breeds 6-7 months 8-10 months
Large Breeds 7-8 months 10-14 months