Your body is made of roughly 37 trillion cells. That is the estimate a 2013 study reached by adding up cell counts organ by organ and cell type by cell type.

A 2013 study estimated the adult human body contains about 37.2 trillion cells.

E. Bianconi and colleagues published the estimate in Annals of Human Biology in 2013. Instead of relying on a single rough calculation, they compiled current estimates of cell numbers for a variety of organs and cell types.

Those partial data add up to a total of 3.72 x 10^13 cells, about 37.2 trillion. The authors write that knowing the total cell number is important from a cultural, biological, medical and comparative modeling point of view.