Hamster Gestation Calculator

Hamster pregnancy uses 16 days here, reflecting Syrian hamsters; dwarf hamsters may deliver later in the 15 to 22 day planning window. Enter the mating date.

Hamster gestation at a glance

Average used by this calculator	16 days (about 2.3 weeks)
Window shown by this calculator	15 to 22 days after breeding
Due date formula	Breeding date + 16 days
Newborn	Pup
At birth	Hairless, with eyes and ears closed

Merck gives 16 to 17 days for Syrian hamsters; Newkirk reports that first Phodopus dwarf-hamster litters arrive after 18 or 19 days, and a laboratory-animal text gives Chinese hamsters 20.5 days. Newkirk also reports that subsequent litters conceived during postpartum estrus are routinely, but not always, delayed beyond 18 days.

Hamster pregnancy timeline

Days 5 and 9, Syrian hamsters	A laboratory-animal medicine chapter describes postovulatory discharge checks; discharge then suggests the female is cycling, not pregnant.
From day 7, Syrian hamsters in one study	Researchers detected pregnancy by ultrasound in a small golden-hamster study.
About day 10, Syrian hamsters	Weight gain and belly swelling may become visible.
At least 2 days before birth, Syrian hamsters	A laboratory-animal medicine chapter says the female can be moved to a separate nesting cage.

Frequently asked questions

How long is a hamster pregnant?

The hamster calculator uses 16 days and a 15 to 22 day planning window; Merck reports that gestation differs among hamster varieties.

How do I calculate a hamster pup due date?

Enter the mating date and the hamster calculator adds 16 days for an estimated pup due date, then shows a 15 to 22 day Delivery Planning Window.

Do Syrian and dwarf hamsters have the same gestation length?

No. Merck says Syrian hamsters are usually pregnant for 16 to 17 days. Newkirk reports that first Phodopus dwarf-hamster litters arrive after 18 or 19 days, while a laboratory-animal medicine text gives 20.5 days as the Chinese hamster average.