Answer by Floris bag. Confidence votes 50. The average size of a human cell varies quite a lot. a single nerve cell can be up to a meter long while a cheek cell averages about 50 micrometers or .05 mm. the average cell though is between 10 micrometers and 100 micrometers.he average female brain capacity is 79.3 cubic inches, slightly smaller than the male … brain of 88.5 cubic inches. The largest human brains may be twice those of average size, but size has no relevance to brain performance.