CollarDog Calculators for Every Stage
A free toolkit for breeders and pet parents, covering your dog's whole reproduction journey: from her heat cycle and fertile window to pregnancy, whelping, and how big the puppies will grow.
Choose Your Calculator
Each tool gives a clear estimate with an honest range, plus guidance and a reminder to check with your vet.
Pregnancy & Gestation
Find her due date and whelping window from the mating or ovulation date, with a week-by-week gestation timeline.
Open calculatorPuppy Weight
Predict a puppy's adult size and weight from its current age, weight, and breed size category.
Open calculatorHeat Cycle
Estimate her next season and fertile window from her last heat date and breed size.
Open calculatorOvulation
Estimate the fertile window and best breeding days from the first day of her heat.
Open calculatorDog Age
Convert your dog's age into human years with the modern vet formula, adjusted for size.
Open calculatorCoat Color Genetics
Predict puppy coat colors from the parents' genetics, with a double-merle safety warning.
Open calculatorHow the Tools Connect
The calculators follow the real timeline of a breeding, so you can move from one step to the next.
Heat & Ovulation
Track her heat cycle and find the fertile window to plan the mating at the right time.
Pregnancy & Whelping
Once she is bred, calculate the due date and whelping window and follow the 9-week timeline.
Puppy Growth
After the litter arrives, estimate how big each puppy will grow as an adult.