Canine Heat Cycle Calculator – Track Your Dog’s Cycles

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Canine Heat Cycle Calculator

Track and predict your female dog’s heat cycle stages with precision

Heat Cycle Prediction Results

Current Cycle Timeline

Proestrus (7-10 days)
Estrus (5-9 days)
Diestrus (60-90 days)
Anestrus (4-5 months)

Important Note

This calculator provides estimates based on typical patterns. Individual dogs may vary significantly. Always consult with your veterinarian for specific advice regarding your dog’s health and reproductive cycle. This calculator is not a substitute for professional veterinary care.

Heat Cycle Stages Explained

Proestrus Stage (7-10 days)

  • Vulva begins to swell
  • Bloody vaginal discharge appears
  • Attracts male dogs but not receptive to mating
  • May show behavioral changes
  • Increased urination frequency

Estrus Stage (5-9 days)

  • Most fertile period
  • Receptive to mating
  • Discharge may become lighter or straw-colored
  • Ovulation typically occurs
  • May exhibit “flagging” behavior (tail to side)

Diestrus Stage (60-90 days)

  • No longer receptive to mating
  • Discharge stops and vulva returns to normal
  • Either resting or pregnant
  • May show false pregnancy symptoms
  • Progesterone levels remain elevated

Anestrus Stage (4-5 months)

  • Sexual dormancy period
  • No signs of heat
  • Reproductive system rests and recovers
  • Normal behavior and activity
  • Prepares for next cycle

Signs to Watch For

Physical Signs

  • Swollen vulva
  • Vaginal discharge (bloody to straw-colored)
  • Frequent urination
  • Excessive licking of genital area
  • Changes in tail position

Behavioral Changes

  • Increased attention seeking or withdrawal
  • Changes in appetite
  • Restlessness or agitation
  • Nesting behaviors
  • Attraction to or from male dogs

Breed Variations

Small Breeds

  • First heat: 4-6 months
  • Cycle frequency: Every 4-6 months
  • May cycle up to 3 times per year
  • Generally shorter cycle duration

Large & Giant Breeds

  • First heat: 18-24 months
  • Cycle frequency: Every 8-12 months
  • Some may cycle only once per year
  • Longer cycle duration overall

Health Considerations

When to Consult a Veterinarian

  • Irregular cycle patterns
  • Excessive bleeding or unusual discharge
  • Signs of distress or illness
  • First heat in young or mature dogs
  • Persistent symptoms after cycle ends

Spaying Considerations

  • Eliminates heat cycles
  • Prevents unwanted pregnancies
  • Reduces risk of certain cancers
  • May reduce behavioral issues
  • Discuss timing with your vet

References

  1. Cornell University College of Veterinary Medicine. “Dog estrous cycles.” Cornell University College of Veterinary Medicine, 2023.
  2. American Kennel Club. “How Long Are Dogs in Heat? What to Know About Heat Cycles.” AKC Expert Advice, 2025.
  3. VCA Animal Hospitals. “Estrous Cycles in Dogs.” VCA Canada Animal Hospitals, 2025.
  4. PetMD. “Dogs In Heat: Timeline, Duration, and Symptoms.” PetMD, 2025.
  5. WebMD Pets. “Dog in Heat (Canine Estrus): Symptoms and Spaying.” WebMD, 2024.
  6. Merck Veterinary Manual. “Estrous (Heat) Cycle in Female Dogs.” Merck & Co., Inc., 2023.

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