The usual range
Perimenopause is the stretch of time before your last period, when the ovaries wind down unevenly and hormones fluctuate rather than simply fall. For many women it gets under way in the mid-forties and lasts about four years, though a shorter or considerably longer transition is entirely normal (Journal of Clinical Endocrinology & Metabolism, 2021).
Menopause itself is only confirmed in hindsight, twelve months after your final period. Everything before that point, with all its irregular cycles and shifting symptoms, is perimenopause. So the length is only ever clear once it is behind you.
What makes it longer or shorter
There is no single switch. The transition tends to be longer when it starts earlier, and its symptoms can outlast the periods themselves. Hot flushes and night sweats are a good example, they can persist for up to ten years, well beyond the last period for some women (Maturitas, 2023).
Genetics, whether you smoke, and other health factors all nudge the timeline, but none of them let you predict your own length in advance. This is why a countdown is the wrong way to think about it. The useful question is not how many months remain, but what is changing in your body now.
How you know it is ending
The clearest sign that perimenopause is drawing to a close is that your periods space out further and further, with longer and longer gaps, before stopping altogether. Vasomotor symptoms often peak around the final period and then ease over the years that follow, though the pace is very individual.
Because the end is only confirmed twelve months after the fact, there is no moment of certainty in real time. What you can see is the trend, the gradual lengthening of gaps, the changing shape of your symptoms, the slow settling on the other side.
When to talk to a GP
A long transition is not, in itself, a problem. But see your GP if your periods become very heavy, come closer together, arrive between your usual cycles, or start again after you thought they had stopped, as bleeding after a year with no periods always needs checking. Symptoms that begin before 45 are also worth a conversation, since they warrant a different assessment. anna does not diagnose, and this article is not medical advice.