Rat Pregnancy Calculator

*Uses an average 21 day gestation period for a Brown Rat. Brown Rat gestation periods can generally be anywhere from 20-22 days.

Rat Pregnancy Calculator: About the Results

The Brown Rat Pregnancy Calculator is a much simpler process to use than the traditional Rat Gestation Chart where you had to count the days until your rat’s due date. Since it is such a short gestation period, they can have up to 5 litters a year.

Important Guidelines in Using Our Rat Pregnancy Calendar Calculator

GestationCalculator.com is providing this mobile friendly Rat Pregnancy Calculator as a service to the rat owner community to help website visitors answer the question ‘What is a Brown Rat’s due date?’ or ‘How Long Are Rats Pregnant For?’ or ‘How Long is a gestation period for rats?’. It’s important that you enter the 1st day your Rat was bred for it to work properly. Try using any of our other gestation calculators just for fun! Please direct any questions you may have to askabreeder@gmail.com.

Gestation Period for Brown Rats

The Gestation Period for Rats is approximately 20-22 days from the first breeding. The Rat Gestation Period Calculator above attempts to generalize the estimation of the due date without any additional factors using a 21 day gestation period for rats.