Many moms-to-be think it’s cute to compare the size of a growing baby to inanimate objects. At week 5, for instance, your baby is around the size of a pea. At week 10, the fetus is the size of an heirloom tomato. But a new website called How Many Big Macs Is My Baby? is making a slightly less common comparison. Just as it promises, the site will tell you your baby’s weight in terms of McDonald’s Big Macs. The weight of a Big Mac that they used was approximately 0.48 pounds, using their calculator.

The comparison is by weight, not size; so it’s not like at 39 weeks your womb will grow to the size of 15 Big Macs. But your baby could weigh that much — at least, according to this website’s projections. Here are some other fun things this website can teach you: It takes the average baby a whole 19 weeks to weigh one whole Big Mac. And at 42 weeks, when the average pregnant woman is ready to pop, the average baby weighs 17 Big Macs.

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