Menopause Calculator
Estimate when menopause is likely, from family history, smoking and the population median.
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The most consistently replicated modifiable factor
Menopause is diagnosed looking backwards: twelve consecutive months without a period, with no other cause. No calculator can predict it, and no blood test reliably does either. Periods stopping before 45 (early menopause) or before 40 (premature ovarian insufficiency) should always be discussed with a doctor.
This estimates where you are in the menopause transition from your age and cycle history.
Timing varies widely between individuals and cannot be predicted precisely, which the page is explicit about.
The stages of menopause
Menopause is not a phase. It is a single point in time, defined retrospectively as 12 consecutive months without a period. You only know it happened once a year has passed.
The years leading up to it are perimenopause, and that is what most people mean when they say menopause. It commonly lasts four to eight years, often begins in the mid-forties, and is when the symptoms occur: irregular cycles, hot flushes, disturbed sleep, mood changes.
The average age of menopause is around 51, with a normal range of roughly 45-55. Before 45 is called early menopause; before 40 is premature ovarian insufficiency and warrants medical assessment.
Perimenopause is the long phase and the one with symptoms. Menopause itself is a date you can only identify looking backwards.
What to enter
- Current age
- The average is around 51 with a normal range of 45-55, so age gives context rather than a prediction.
- Date of last period
- Twelve consecutive months without one is the definition of menopause having occurred.
- Cycle changes
- Increasing irregularity is usually the first sign of perimenopause, often before any other symptom.
- Mother's age at menopause
- Weakly predictive. There is a genetic component, and it is not strong enough to rely on.
What influences timing
- Genetics
- The strongest single factor. Family history gives some indication, though not a reliable prediction.
- Smoking
- Associated with menopause roughly one to two years earlier on average.
- Surgery
- Removal of both ovaries causes immediate surgical menopause, regardless of age.
- Cancer treatment
- Chemotherapy and pelvic radiotherapy can bring it forward or cause it directly.
- Premature ovarian insufficiency
- Menopause before 40. Affects about 1% of women and needs medical assessment.
What this assumes
Individual timing cannot be predicted reliably. Age, family history and symptoms give context, not a date.
Hormonal contraception can mask the transition entirely by controlling bleeding, which makes cycle-based assessment unreliable.
How to calculate your menopause timeline
Work out which stage you are in. Predicting the date is not something the evidence supports.
- perimenopause
- Everything before that point, once cycles begin changing
- postmenopause
- Everything after it
Track your cycles. Increasing variability in length is usually the earliest sign, and it often appears before other symptoms.
Note the date of your last period. The twelve-month count starts there, and it resets if a period occurs.
Consider your age in context. 45-55 is the normal range. Before 45 is early; before 40 warrants medical assessment.
Discuss symptoms with a clinician. Perimenopausal symptoms are treatable. Hormone therapy and non-hormonal options both exist, and the risk-benefit balance is individual.
See a worked example: identifying the stage
- Age
- 48
- Cycles
- Ranging 21 to 45 days over the past year
Irregular cycles at 48 are consistent with perimenopause, which commonly begins in the mid-forties.
Menopause itself has not occurred, since periods are still happening.
It will be confirmed retrospectively, once twelve consecutive months pass without one.
In the meantime, pregnancy is still possible. Contraception is generally advised until 12 months after the last period, or 24 months if under 50.
Perimenopause, with menopause confirmed only in hindsight
Frequently asked questions
Around 51, with a normal range of roughly 45 to 55.
Before 45 is considered early menopause. Before 40 is premature ovarian insufficiency, affects about 1% of women, and should be assessed medically.
Perimenopause is the transition, commonly lasting four to eight years, when hormones fluctuate and symptoms occur. Menopause is a single point: 12 consecutive months without a period.
Most people using the word menopause mean perimenopause, since that is the phase with symptoms. The distinction matters clinically, particularly for contraception.
Yes. Fertility declines but does not stop, and ovulation still occurs unpredictably during perimenopause.
Standard guidance is to continue contraception for 12 months after the last period if over 50, or 24 months if under 50. Unplanned pregnancy in perimenopause is not rare.
Not reliably for an individual. AMH blood tests give some indication of ovarian reserve and are not accurate enough to predict a date.
Family history offers a weak signal, since there is a genetic component. Anyone offering a specific predicted year is overstating what can be known.
Changing cycle length is usually first, often before anything else is noticed. Cycles become shorter, then longer and more variable.
Hot flushes, disturbed sleep, mood changes, brain fog and vaginal dryness commonly follow. The pattern and severity vary enormously between individuals.
It is the most effective treatment for hot flushes and night sweats, and understanding of its risk-benefit balance has shifted considerably since the early 2000s.
For most healthy women under 60 or within ten years of menopause, benefits generally outweigh risks. It is genuinely individual and depends on your history, so it is a conversation with a clinician rather than a rule.
Problems people actually run into
Stopping contraception too early
Irregular periods signal declining fertility, not the end of it. Ovulation still happens unpredictably throughout perimenopause.
Guidance is 12 months after the last period if over 50, and 24 months if under 50. Stopping at the first missed period is a common and consequential error.
Attributing every symptom to perimenopause
Thyroid disease, anaemia, depression and diabetes all cause fatigue, mood changes and sleep disruption, and they become more common at the same age.
Worth ruling those out rather than assuming. They are treatable, and attributing everything to hormones can delay diagnosis by years.
Results are estimates for general information only and are not professional financial, medical, or legal advice. Read our full disclaimer.
Last updated: September 4, 2026