How many human cells are there in our body, on average?

Question

How many human cells are there in our body, on average? Wikipedia (http://en.wikipedia.org/wiki/Human_microbiome) says 10¹³:> Bacterial cells are much smaller than human cells, and there are at least ten times as many bacteria as human cells in the body (approximately 10¹⁴ versus 10¹³).The [Nobel site](http://www.nobelprize.org/nobel_prizes/medicine/laureates/2001/press.html) says 10¹⁴:> An adult human being has approximately 100 000 billion cells, all originating from a single cell, the fertilized egg cell.The [Physics fact book](http://hypertextbook.com/facts/1998/StevenChen.shtml) insists it's 10¹³:> (length of 1 bp)(number of bp per cell)(number of cells in the body) > (0.34 * 10^-9 m)(6 * 10⁹)(10¹³)Finally, [Wolfram Alpha](https://www.wolframalpha.com/input/?i=number+of+cells+in+body) gives 1.0 × 10¹⁴ as fact:> Estimated number of eukaryotic (human) cells in the human body: 1.0*10¹⁴I am quite confused: *who is right here?*

Answer 1

The exact number is unknown. Many credible resources use different methods to arrive at different answers. I would recommend using a range that includes all of your resources.