There is no formal answer to this question. Because a midlife crisis is not recognized as a medical condition (see more about this in our article ‘what is a midlife crisis?’) there are no statistics on the condition.
Psychological studies and media surveys put the figure at around 10% of the male population (these figures only relate to western/developed countries) and between 3-5% of women. The estimate vary widely and are influenced by the location, social standing and cultural background of the people surveyed.
In reality there are no solid figures to rely on. The true number of people suffering from a midlife crisis is unknown, but what we know is that number of people looking for help and support is high, in the hundreds of thousands in the UK and in the USA alone.
Read more about why we don’t know the true scale of the problem in our article Why is the number of people suffering from midlife crisis unknown?