Here is some information which might help from past posts:
There is a book called, "Fibroids: The Complete Guide to Taking Charge of Your Physical, Emotional, and Sexual Well-Being' by Johanna Skilling: It says, the average uterus is 2 to 4 inches long, 1.5 to 2.5 inches wide and 1 inch thick; it weighs about one-sixth of a pound or 50 grams ... If you've ever been pregnant, your uterus may be on the larger end of those dimensions.
That's an equivalent of 5.08 X 10.16 cm long and 3.8 X 6.35 cm wide and 2.54 cm thick.
(this came from http://www.fibroiduae.com/fibro5.htm#anchor66303):
Q: I am confused as to the way the size of a uterus is compared to the size of a pregnant uterus at different months. Could you give me some way to understand this?
A: According to Obstetricians/Gynecologists, the estimation of fibroid size (based on the model of the size of a uterus in pregnancy) goes like this:
(1) 12 weeks - just up to the level of the pubic bone
(2) 16 weeks - 4 fingerbreadths above the pubic bone
(3) 18 weeks - 2 fingerbreadths below the navel
(4) 20 weeks - at the navel
(5) 24 weeks - 1 fingerbreadth above the navel
(6) 28 weeks - 3 fingerbreadths above the navel
There is one problem with this model, i.e., the top of a Fibroid Uterus can be very irregular, whereas the top of a Pregnant Uterus is usually smooth and uniform. Although it complicates this method of "sizing" fibroids, it is still useful and the most comon way Gynecologists record uterine size.
There are a number of other ways that Gynecologists use to describe fibroid size - often using a comparison to commonly used items. The following "Bestiary" of items might help visualization by translation into actual measurement!
Average Sizes of Items
Pea - 1cm (3/8")
Walnut - 3cm (1 3/16")
Lemon (diameter) - 5.5cm (2 3/16")
Apple/Pear - 7.5cm (3")
Orange - 9cm (3 1/2")
Grapefruit - 11.5cm (4 1/2")
I hope this helps!