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Mouse Gestation Calculator
Mouse pregnancy uses 20 days in this calculator, with a 19 to 21 day planning window after mating. Enter the mating date below.
Mouse gestation at a glance
| Average used by this calculator | 20 days (about 2.9 weeks) |
|---|---|
| Window shown by this calculator | 19 to 21 days after breeding |
| Due date formula | Breeding date + 20 days |
| Young | Pups |
| Average litter | 5 to 12 pups in Merck professional data |
Merck reports newborn mice are deaf and blind and separately advises leaving a new litter undisturbed for at least seven days. A female mated right after giving birth may have delayed implantation during lactation, placing a later birth outside this calculator's planning window.
Mouse breeding and birth timeline
| Mating date | The calculator starts with the entered mating date. |
|---|---|
| Days 19 to 21 | Merck gives this as the usual mouse gestation period. |
| At least 7 days after birth | Merck advises leaving the litter undisturbed. |
| Around 2 weeks after birth | Baby mice begin to look like small adults. |
| About day 21 after birth | Weaning takes place around this age. |
Frequently asked questions
How long is a mouse pregnant?
The mouse calculator uses 20 days after mating and a 19 to 21 day planning window within Merck's range for an ordinary pregnancy. A female mated right after giving birth may have delayed implantation during nursing and deliver later.
How do I calculate a mouse due date?
Enter the mating date and the mouse calculator adds 20 days for an estimated pup due date and shows a 19 to 21 day Delivery Planning Window.
What are newborn mouse pups like?
Merck says mouse pups are born deaf and blind and that the litter should not be disturbed for at least seven days.
When should I call a veterinarian during mouse birth?
If mouse birth appears abnormal, contact a veterinarian promptly.
Sources
- Merck Veterinary Manual: Breeding and Reproduction of Mice
- Merck Veterinary Manual: Mice and Rats As Pets
Reviewed by Elliott Garber, DVM · Last reviewed
