Dogs are pregnant for about 63 days, counted from ovulation. The complication is that most owners only know the mating date, and a bitch can be mated several days before she ovulates because sperm survive in the reproductive tract. Counted from a mating, normal whelping therefore falls anywhere from 58 to 68 days later. This calculator gives the most likely date, that whole window, and a timeline of what to expect and when to involve your vet.
Gestation from ovulation is very consistent in dogs, at about 63 days, give or take a day or two. If your vet timed ovulation with progesterone blood tests, count 61 to 65 days from the estimated ovulation date — that is the most accurate way to predict whelping.
From a mating date alone, the window widens to 58 to 68 days. If there were several matings, enter the first. Small litters sometimes run slightly longer and large litters slightly shorter, but anything outside the window is a reason to call your vet.
There is no reliable home test. An ultrasound scan from about day 25 can show heartbeats; a vet may be able to feel the pregnancy through the abdomen at roughly days 28 to 35; and a blood test for the hormone relaxin becomes positive from about day 25 to 30.
An X-ray after about day 45, once the puppies' skeletons have mineralised, is the most reliable way to count them. Knowing the number matters: it tells you when she has finished whelping.
For the first two thirds she needs no extra food, and overfeeding early makes whelping harder. From about day 42, when the puppies grow fastest, most vets recommend changing gradually to a good-quality puppy or growth food and splitting it into smaller, more frequent meals, because the uterus crowds her stomach.
Avoid calcium supplements unless your vet prescribes them: extra calcium in pregnancy is linked to a dangerous drop in blood calcium (eclampsia) after whelping. Keep exercise gentle and regular, and ask your vet about worming and any medication before giving it.
From about day 55, take her rectal temperature twice a day. Normal is roughly 100.5 to 102.5°F (38 to 39°C). A drop to below about 99°F (37.2°C) usually means labour will start within 24 hours. Nesting, restlessness, panting and refusing food are common in the hours before.
Call your vet if she strains strongly for 30 minutes without producing a puppy, if more than two to four hours pass between puppies when you know more are due, if there is green or bloody discharge before the first puppy, or if she reaches day 68 from the mating without starting.
About 63 days from ovulation. From a mating date, normal whelping ranges from 58 to 68 days, because mating can happen a few days before ovulation.
Early signs are subtle — a slight drop in appetite, then weight gain and enlarging nipples from about four to five weeks. Confirmation needs a vet: ultrasound from about day 25, palpation around days 28–35, a relaxin blood test from about day 25–30, or an X-ray after day 45.
Most vets recommend a gradual switch to a puppy or growth formula from about day 42, the start of the last third, when the puppies grow fastest. Feed smaller meals more often. Do not add calcium supplements unless your vet prescribes them.
A rectal temperature below about 99°F (37.2°C), from a normal of roughly 100.5–102.5°F, usually means labour within 24 hours. Take it twice a day from about day 55 so you know her normal.
If she is beyond 68 days from the first mating, or beyond 65 days from a progesterone-timed ovulation, call your vet. The same applies earlier if she shows discharge, strains without producing a puppy, or seems unwell.