The question sounds like it should have a clean answer, and technically it does. The average age of menopause in the UK is 51. Then you meet a woman who finished at 44 and another still bleeding at 55, and both were entirely normal, and the number stops feeling like much of an answer.
Part of the trouble is that menopause is not a phase. It is a single day, and you can only identify it looking backwards: the day that marks twelve months since your last period. Almost everything you associate with menopause happens before that day, during perimenopause. So when a woman asks what age menopause starts, she is usually asking two questions at once, and only one of them has a tidy average.
Menopause: 51 on average. That is the UK figure and it sits close to the average across most of Europe and North America. The ordinary range runs from about 45 to 55. Finishing at 46 is not early in any medical sense, and 54 is not late.
Perimenopause: usually the mid-forties, sometimes the late thirties. This is the part that changes your daily life, and it typically runs about four years. For some women it is a matter of months. For others it stretches closer to a decade, which is why "I have been like this for eight years" is a sentence clinicians hear regularly and should never dismiss.
Early menopause: between 40 and 45. Around one woman in twenty. Common enough that it should never be met with surprise, and it is managed differently from menopause at 51.
Premature ovarian insufficiency: before 40. Roughly one woman in a hundred, and about one in a thousand before the age of 30. This is a diagnosis rather than simply an early finish, and it carries long-term bone and cardiovascular considerations that make treatment the default rather than a preference. If this is where you are, early menopause before 45 covers it properly.
Your mother's age, more than any other single factor. Genetics is the strongest predictor we have, though it is a tendency rather than an inheritance. If she cannot remember, or had a hysterectomy that took the question away, you have lost your best clue and there is no test that replaces it.
Smoking, by one to two years. This is one of the few modifiable factors with consistent evidence behind it. The effect appears to be dose-related, and stopping seems to reduce it.
Cancer treatment. Chemotherapy and pelvic radiotherapy can bring menopause forward, sometimes suddenly and sometimes years later. Whether it is temporary or permanent depends on the drugs, the dose and your age at the time.
Surgery. Removing both ovaries brings menopause the same day, with no transition and often more intense symptoms, which is a different experience from the gradual version. Removing the uterus while keeping the ovaries does not cause menopause, but it does tend to bring it forward by a year or two, and it takes away your clearest signal, so it can arrive unannounced. Surgical menopause explains why the abrupt version hits harder.
Certain autoimmune and genetic conditions, including some thyroid disorders, Turner syndrome and Fragile X premutation carrier status. This is one reason a diagnosis of premature ovarian insufficiency should prompt further investigation rather than a prescription and a goodbye.
Ethnicity, modestly. The SWAN study, which followed a large multi-ethnic group of American women through the transition, found Black and Hispanic women reached menopause slightly earlier on average and Japanese and Chinese women slightly later than white women. These are population averages and they tell you very little about any individual woman.
Never having been pregnant is associated with a slightly earlier menopause, and having several pregnancies with a slightly later one. The effect is small and not something to make decisions on.
The pill does not delay menopause. It masks it. The bleed you have on the pill is a withdrawal bleed, produced by stopping the hormones for a few days, not evidence that your ovaries are still ovulating. You can be well into perimenopause and still bleeding monthly on schedule, which is exactly why some women only discover where they are when they come off it. Coming off the pill covers what that reveal looks like.
The age you started your periods is a weak predictor at best. "Early periods, early menopause" is a tidy story built on unconvincing evidence, and it has worried a lot of women unnecessarily.
No home test can usefully tell you how many eggs you have left. AMH predicts how ovaries respond to IVF stimulation reasonably well, and predicts your menopause date poorly. It is a fertility planning tool that has been marketed as a crystal ball. Should you test your hormones? goes through what each test can and cannot do.
Diet and lifestyle move the timing very little, smoking aside. They make a substantial difference to how the transition feels, which is a better reason to bother with them than trying to postpone a date you cannot postpone.
The first reliable sign is not a hot flush. It is a change in the rhythm of your cycle.
The international staging system used by researchers, STRAW+10, calls it early perimenopause when consecutive cycles start differing by seven days or more, and late perimenopause once you have gone sixty days or more without a period. Not a shorter cycle or a longer one specifically. Cycles that have stopped being predictable.
Alongside that, the symptoms that arrive early and get attributed to everything else: sleep that breaks at three in the morning, anxiety with no cause attached to it, a shorter fuse than you recognise, heavier or more erratic bleeding, joints that ache in the morning. The first signs of perimenopause covers the ones that get missed, and the free menopause stage quiz maps your own pattern onto the STRAW+10 stages in a couple of minutes.
UK guidance is explicit: in women over 45 with typical symptoms, perimenopause and menopause are diagnosed on symptoms and cycle pattern, not on FSH. This is not cost-cutting. It is because FSH swings dramatically from week to week during the transition, so a normal result on a Tuesday tells you about that Tuesday and very little else.
Testing earns its place in three situations: under 40, where premature ovarian insufficiency needs confirming with two raised FSH readings taken four to six weeks apart; between 40 and 45, where it adds something to the picture; and where something else needs ruling out, because thyroid problems and iron deficiency produce a symptom list that overlaps almost completely with perimenopause. Thyroid or hormones? is worth reading before you accept either answer, and the perimenopause blood test guide explains what to ask for and when in your cycle to have it done.
Contraception. Fertility falls in perimenopause but does not vanish, and unplanned pregnancy at 47 happens more often than the assumption suggests. The usual advice is to continue contraception for two years after your last period if you are under 50, and one year if you are over 50. See can you get pregnant in perimenopause.
Bone and heart. Oestrogen protects bone density and influences cardiovascular risk, so an earlier menopause means more years without that protection. This is the reason age at menopause is a genuine medical fact about you rather than a piece of trivia. Bone health after menopause covers what actually helps.
Treatment decisions. For premature ovarian insufficiency and early menopause, hormone therapy is generally recommended until at least the average age of menopause, and the risk calculation is not the same one that applies to a woman starting HRT at 52. If that is your situation, the HRT guide and the free HRT checker will help you arrive at an appointment with the right questions, and HRT side effects covers what to expect in the first months.
Do not accept "you are too young for that" as a diagnosis. It is the most common thing women with premature ovarian insufficiency are told, and the average delay to diagnosis is measured in years, not weeks.
If you are under 40 with periods that have become irregular or stopped, and there is no other obvious explanation, you are entitled to two FSH tests four to six weeks apart, along with thyroid function, prolactin and a pregnancy test. If your GP is unwilling, asking for a referral to a menopause specialist or gynaecologist is reasonable, and so is asking for the refusal to be recorded.
Can menopause start at 40?
Yes. Menopause between 40 and 45 is called early menopause and affects around one woman in twenty. Before 40 it is premature ovarian insufficiency and needs proper investigation rather than reassurance.
How long does perimenopause last?
About four years on average, though the range runs from months to roughly a decade. How long menopause symptoms last sets out what continues after periods stop.
Does the pill delay menopause?
No. It masks the signs by producing a regular withdrawal bleed, so you may not notice the transition until you stop taking it.
Can I find out when my menopause will be?
Not reliably. Your mother's age is the best available clue, and no blood test currently predicts an individual woman's date with any useful accuracy.
Sources: NICE NG23, Menopause: diagnosis and management · Harlow SD et al., Executive summary of the Stages of Reproductive Aging Workshop +10, J Clin Endocrinol Metab 2012;97(4):1159-68 · Gold EB et al., Factors associated with age at natural menopause in a multiethnic sample (SWAN), Am J Epidemiol 2013 · European Society of Human Reproduction and Embryology guideline on premature ovarian insufficiency, 2015 · Faculty of Sexual and Reproductive Healthcare, Contraception for Women Aged Over 40 Years · Educational only, not medical advice.
Keep reading: The first signs of perimenopause · Perimenopause vs menopause · Early menopause before 45 · How long do menopause symptoms last? · Find your menopause stage (free) · Take the free Hormone Quiz