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Pregnancy & Litters

A window to plan around.

Enter a known mating date for a possible delivery range. For dogs, a veterinarian-timed LH surge can provide a narrower reference.

01

Start with a known date

Example values

An LH surge is not the same as a mating or ovulation date.

Use the date from your records. Dates are counted in calendar days.

The calculator cannot predict litter size. Arrange pregnancy confirmation and birth planning with your veterinarian.

Possible delivery window

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A little context helps

What the answer means

01

Know which date you have

For dogs, Merck lists 58–72 days from the first day the female permitted breeding, 64–66 days from the LH surge, or 56–58 days from the first day of diestrus. Merck notes that breeding dates and conception dates don’t line up closely enough to predict whelping accurately.

02

Allow for uncertainty

For cats, this tool uses VCA’s 60–67-day range and shows its 63–65-day average as most likely. A mating-date estimate cannot pinpoint conception or confirm pregnancy.

03

Make a care plan

Your veterinarian can confirm pregnancy, assess the litter and help plan the birth. A calendar result cannot tell you whether labor is normal.

Dogs · near the date

Most dogs’ rectal temperature drops to 98.1–100°F (36.7–37.8°C) 8–24 hours before whelping (Merck).

Cats · near the date

A queen usually stops eating in the last 24 hours before labor, and her temperature may drop below 100°F (37.8°C) (VCA).

Cats · call the vet

VCA says to seek a vet at once if 20 minutes of intense labor produce no kitten, a kitten visible at the vulva isn’t delivered after 10 minutes, the queen is lethargic or feverish (over 103°F), or she bleeds fresh blood for more than 10 minutes.

If your pet is struggling in labor, bleeding, weak or otherwise unwell, contact a veterinarian promptly; do not wait for the calculated window.

Guides in this section

How Long Are Cats Pregnant?Cats are pregnant for 60–67 days, about 9 weeks, most often 63–65. Enter the mating date for the due-date window and a calendar of vet checks, from VCA and the Merck Veterinary Manual.How Long Are Dogs Pregnant?Dogs are pregnant for about 63 days, roughly 9 weeks. Enter a mating or LH-surge date for the due-date window and a calendar of vet checks, from the Merck Veterinary Manual.
Follow the numbers

Sources for this tool

Checked Oct 17, 2026
Merck Veterinary ManualWhelping and Queening in Bitches and QueensDog gestation from first permitted breeding or a veterinarian-timed LH surge; the temperature drop before whelping.VCA Animal HospitalsPregnancy and Parturition in CatsA 60–67-day gestation, averaging 63–65 days; signs of labor and when to call the vet.