When is my dog pregnancy due?
Pick the date you know (the first breeding, the LH surge, ovulation or the first day of diestrus) and type it. The dog pregnancy calculator shows the estimated due date, the normal whelping window, and how many days along she is today.
- Estimated due date
- November 6, 2026
Her puppies are due about November 6, 2026, between October 30, 2026 and November 13, 2026.
- Earliest normal due date
- October 30, 2026
- Latest normal due date
- November 13, 2026
- Days along
- 30
- Days to the estimated due date
- 35
- Where she is now
- Day 30: an ultrasound can confirm the pregnancy.
- Ultrasound check from
- September 27, 2026
- X-ray puppy count from
- October 17, 2026
Answer for the example date Friday, October 2, 2026. It changes to today's date when the page loads.
Estimated due date: November 6, 2026. Her puppies are due about November 6, 2026, between October 30, 2026 and November 13, 2026.
How to calculate
Computes the whelping date window of a pregnant dog from the breeding, LH surge, ovulation or diestrus date, with how many days along she is and when ultrasound and X-ray checks work.
Example with the default inputs (The date I know First breeding, Date of that event September 2, 2026, Today’s date October 2, 2026) on the example date Friday, October 2, 2026: Her puppies are due about November 6, 2026, between October 30, 2026 and November 13, 2026.
Method: Due date = event date + the middle of Merck’s gestation window: 65 days from the first breeding (58 to 72), 65 from the LH surge (64 to 66), 63 from ovulation (62 to 64), 57 from the first day of diestrus (56 to 58).
- Gestation lengths are from the Merck Veterinary Manual; the estimate is the middle of each window.
- Days are counted from the event date as day 0; ultrasound from day 25 and X-ray from day 45 count from the same date.
- Breed, the number of litters and the litter size also change the length, so a vet check is the final word.
Worked examples
Each example is checked against the calculator on every build.
- The date I know First breeding, Date of that event 2026-03-01, Today’s date 2026-04-05 gives Estimated due date 2026-05-05, Earliest normal due date 2026-04-28, Latest normal due date 2026-05-12, Days along 35, Days to the estimated due date 30, Ultrasound check from 2026-03-26, X-ray puppy count from 2026-04-15.Source: Merck Veterinary Manual, Whelping and Queening in Bitches and Queens (58–72 days from the first breeding), https://www.merckvetmanual.com/management-and-nutrition/management-of-reproduction-dogs-and-cats/whelping-and-queening-in-bitches-and-queens
- The date I know LH surge, Date of that event 2026-12-20, Today’s date 2027-02-21 gives Estimated due date 2027-02-23, Earliest normal due date 2027-02-22, Latest normal due date 2027-02-24, Days along 63, Days to the estimated due date 2.Source: Merck Veterinary Manual, Breeding Management of Bitches (parturition 64–66 days after the LH peak), https://www.merckvetmanual.com/management-and-nutrition/management-of-reproduction-dogs-and-cats/breeding-management-of-bitches
- The date I know Ovulation, Date of that event 2028-01-01, Today’s date 2028-03-10 gives Estimated due date 2028-03-04, Earliest normal due date 2028-03-03, Latest normal due date 2028-03-05, Days along 69, Days to the estimated due date -6.Source: Merck Veterinary Manual, Approximate Gestation Periods (dog 62–64 days from ovulation), https://www.merckvetmanual.com/multimedia/table/approximate-gestation-periods
- The date I know Diestrus, Date of that event 2026-06-10, Today’s date 2026-06-10 gives Estimated due date 2026-08-06, Earliest normal due date 2026-08-05, Latest normal due date 2026-08-07, Days along 0, Days to the estimated due date 57.Source: Merck Veterinary Manual, Whelping and Queening in Bitches and Queens (56–58 days from the first day of diestrus), https://www.merckvetmanual.com/management-and-nutrition/management-of-reproduction-dogs-and-cats/whelping-and-queening-in-bitches-and-queens
How it works
The calculator adds a number of days to the date you type. The day lengths come from the Merck Veterinary Manual:
| The date you know | Normal whelping window | Estimated due date |
|---|---|---|
| First breeding (the first day the female accepted the male) | 58 to 72 days later | 65 days later |
| LH surge, or the first rise of progesterone above about 2 ng/mL | 64 to 66 days later | 65 days later |
| Ovulation | 62 to 64 days later | 63 days later |
| First day of diestrus | 56 to 58 days later | 57 days later |
- Estimated due date = event date + the middle of the window ((shortest + longest) ÷ 2, always a whole number of days here).
- Earliest = event date + the shortest length; latest = event date + the longest length.
- Days along = the whole days from the event date to today’s date. The event date is day 0.
- Days to the estimated due date = the middle of the window − days along. It is negative once the date has passed.
- Ultrasound check from = event date + 25 days, and X-ray puppy count from = event date + 45 days. Merck gives day 25 to 35 as the best time for ultrasound and about day 42 to 45 for the skeletons to show on X-ray; the calculator uses the later end so the check is not too early. These days count from the date you type.
- Where she is now, by days along (d): past the window when d is more than the longest length; in the whelping window when d is from the shortest to the longest length; late pregnancy when d is 45 or more; ultrasound can confirm when d is 25 or more; otherwise too early for ultrasound.
Rules. Today’s date may not be before the event date: then there is no answer and the page says so. Both dates are from 1 January 1900 to 31 December 2200. Calendar days are counted with leap days (2028 has 29 February).
Output format. Dates show as month, day and year. Days along and days to the due date are whole numbers.
Worked examples by hand
First breeding on 1 March 2026, counted on 5 April 2026. 1 March + 58 days = 28 April 2026; + 65 days = 5 May 2026; + 72 days = 12 May 2026. From 1 March to 5 April is 35 days, so 65 − 35 = 30 days to go. Ultrasound from 1 March + 25 = 26 March; X-ray from 1 March + 45 = 15 April.
LH surge on 20 December 2026, counted on 21 February 2027. + 64, 65 and 66 days = 22, 23 and 24 February 2027. From 20 December to 21 February is 11 + 31 + 21 = 63 days, so 2 days to go.
Ovulation on 1 January 2028, counted on 10 March 2028. 2028 is a leap year. + 62, 63 and 64 days = 3, 4 and 5 March 2028. From 1 January to 10 March is 30 + 29 + 10 = 69 days, so 63 − 69 = −6 days: the estimate passed 6 days ago and she is past the latest date (day 64).
First day of diestrus on 10 June 2026, counted the same day. + 56, 57 and 58 days = 5, 6 and 7 August 2026; day 0, 57 days to go.
Other questions people ask
How long is a dog pregnant?
About 63 days from ovulation. The Merck Veterinary Manual gives 62 to 64 days from ovulation, 64 to 66 days from the LH surge, 56 to 58 days from the first day of diestrus, and 58 to 72 days from the first breeding.
Why is the window so wide from the breeding date?
Sperm can live for days in the female, and a female may accept the male several days before she ovulates. So the breeding date says little about the day the eggs were fertilized. A vet can time ovulation with progesterone or LH tests, which narrows the window to 3 days.
How is the due date worked out?
The calculator adds the middle of the normal window to your date: 65 days from the first breeding, 65 from the LH surge, 63 from ovulation, or 57 from the first day of diestrus. The earliest and latest dates add the ends of the window.
When can a vet confirm that my dog is pregnant?
Merck says ultrasound works best from day 25 to day 35, and may miss a pregnancy before day 21. A relaxin blood test works after day 22 to 27. The puppies’ skeletons show on a routine X-ray from about day 42 to 45, and an X-ray after day 55 is best to count them.
What if my dog goes past the latest date?
Call your vet. A dog that is past the end of the normal window, or that strains for a long time without a puppy, needs a check.
Does the litter size change the due date?
It can. Merck notes that breed, the number of litters she has had, and litter size all change the length of the pregnancy a little.