Estimate your dog's due date based on the mating date.
Standard Breed (63 Days)
Small Breed (Slightly Earlier)
Large Breed (Slightly Later)
Estimation Results
Earliest Arrival (Day 58)
Latest Arrival (Day 68)
Organ Development (Day 25)
Skeleton Hardens (Day 45)
Understanding the Dog Pregnancy Timeline
The average gestation period for dogs is approximately 63 days from conception, though this can vary between 58 and 68 days. Because the date of mating does not always perfectly align with the date of conception, using a dog pregnancy calculator helps owners prepare for the arrival of puppies within a specific window.
How Long Are Dogs Pregnant?
Dog pregnancy is divided into three trimesters, each lasting roughly 21 days. Unlike humans, where the trimesters are months long, canine development happens extremely rapidly.
First Trimester (Days 1-21): Embryos move to the uterine horns. By the end of this period, a heartbeat may be detectable via ultrasound.
Second Trimester (Days 22-42): The fetuses begin to look like puppies. Development of organs, claws, and whiskers occurs.
Third Trimester (Days 43-63): The puppies are fully formed. The mother will begin searching for a "nesting" spot.
Realistic Example: Golden Retriever
If your Golden Retriever was mated on March 1st, her estimated due date would be May 3rd. You should begin checking her temperature daily starting around April 28th (Day 58) to watch for the "drop" that signals labor is within 24 hours.
Signs of Impending Whelping
As the calculated due date approaches, watch for these specific signs that labor is about to begin:
Temperature Drop: A dog's rectal temperature usually drops below 99°F (37.2°C) approximately 12-24 hours before labor.
Nesting Behavior: Shredding bedding or seeking out a quiet, dark corner.
Loss of Appetite: Many dogs stop eating 24 hours before whelping.
Restlessness: Shivering, panting, or frequent pacing.
How to Use This Calculator
To get the most accurate results, enter the date of the first mating. If your dog was mated multiple times over several days, the window may shift by 48-72 hours. While the average is 63 days, small breeds with large litters often deliver a day or two early, whereas small litters in large breeds may go slightly longer.
function calculateWhelping() {
var dateInput = document.getElementById('matingDate').value;
var resultDiv = document.getElementById('pregnancyResult');
if (!dateInput) {
alert("Please select a mating date.");
return;
}
var matingDate = new Date(dateInput);
// Average Gestation is 63 days
var dueDate = new Date(matingDate);
dueDate.setDate(matingDate.getDate() + 63);
// Earliest window (Day 58)
var earlyDate = new Date(matingDate);
earlyDate.setDate(matingDate.getDate() + 58);
// Latest window (Day 68)
var lateDate = new Date(matingDate);
lateDate.setDate(matingDate.getDate() + 68);
// Milestones
var organDate = new Date(matingDate);
organDate.setDate(matingDate.getDate() + 25);
var skeletonDate = new Date(matingDate);
skeletonDate.setDate(matingDate.getDate() + 45);
// Formatting dates
var options = { month: 'long', day: 'numeric', year: 'numeric' };
document.getElementById('mainResultText').innerHTML = "Your dog is expected to whelp on or around " + dueDate.toLocaleDateString(undefined, options) + ".";
document.getElementById('earlyDate').innerText = earlyDate.toLocaleDateString(undefined, options);
document.getElementById('lateDate').innerText = lateDate.toLocaleDateString(undefined, options);
document.getElementById('organDate').innerText = organDate.toLocaleDateString(undefined, options);
document.getElementById('skeletonDate').innerText = skeletonDate.toLocaleDateString(undefined, options);
resultDiv.style.display = 'block';
// Smooth scroll to result
resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}