The mean corpuscular volume (MCV) is calculated using the formula: \[ \text{MCV} = \frac{\text{Hematocrit (\%)}}{\text{RBC count (millions per microliter)}} \times 10 \] The value is expressed in femtoliters. An MCV within the range of 80-100 fl is considered normal for adults. Deviations from this range can indicate various medical conditions.