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Postmenopause Calculator

HealthMedical Reference

The final period before at least 12 months with none.

Usually today; change it to look back or ahead.

Your stage —
Menopause date (12 months after last period)
—
Time since last period
—
Years since menopause
—
STRAW+10 stage
—
Next milestone
—
Age at the measured date
—

Menopause is dated retrospectively: it is the day 12 months after the final menstrual period, and everything after it is postmenopause. A last period on 15 March 2020 puts menopause on 15 March 2021. The STRAW+10 system then splits postmenopause into stages +1a and +1b (one year each), +1c (to roughly year 8) and +2 for the rest of life.

About this tool

Many people only know menopause has happened in hindsight, once a full year has passed without a period. This calculator takes the date of your last period and a date to measure to, then returns the confirmed menopause date, the time since the final period in years and months, the years spent postmenopausal and the stage under the STRAW+10 reproductive aging framework used in research and clinical reporting. Adding your age at the last period gives your age at the measured date and flags early or premature menopause. The staging is based on time alone; it cannot tell a natural final period from a pause caused by illness, breastfeeding, contraception or surgery, and the boundary between +1c and +2 varies between individuals by a few years.

How to use it

  1. Enter your last period

    Pick the date of the final menstrual period before the run of months without one.

  2. Set the measure-to date

    Leave it at today or move it to see your stage at another date, past or future.

  3. Add your age if you like

    Optional: it adds your current age and notes if the final period came before 45.

  4. Read the stage and working

    The stage, menopause date and next milestone update as you type, with the month count shown in the working.

Examples

Last period 15 March 2020

Date of your last menstrual period
2020-03-15
Measure to
2021-03-15

Result Your stage: Early postmenopause (+1b)
Menopause date (12 months after last period): March 15, 2021
Time since last period: 1 yr 0 mo
Years since menopause: 0
STRAW+10 stage: +1b
Next milestone: Stage +1c from March 15, 2022
Age at the measured date: Add your age

  1. Last period: March 15, 2020; as of March 15, 2021 = 365 days (1 yr 0 mo)
  2. Menopause date = last period + 12 months = March 15, 2021
  3. Years since menopause = 0 ÷ 365.25 = 0
  4. STRAW+10 stage by months since last period (12): under 12 = +1a, 12–23 = +1b, 24–95 = +1c, 96+ = +2

Exactly twelve months without a period confirms menopause on 15 March 2021, and the second year after the final period begins.

Last period June 2018, age 52

Date of your last menstrual period
2018-06-10
Measure to
2024-06-10
Age at last period
52

Result Your stage: Early postmenopause (+1c)
Menopause date (12 months after last period): June 10, 2019
Time since last period: 6 yr 0 mo
Years since menopause: 5
STRAW+10 stage: +1c
Next milestone: Stage +2 from about June 10, 2026
Age at the measured date: 58

  1. Last period: June 10, 2018; as of June 10, 2024 = 2192 days (6 yr 0 mo)
  2. Menopause date = last period + 12 months = June 10, 2019
  3. Years since menopause = 1827 ÷ 365.25 = 5
  4. STRAW+10 stage by months since last period (72): under 12 = +1a, 12–23 = +1b, 24–95 = +1c, 96+ = +2

Six years after the final period sits inside STRAW+10 stage +1c, five years past the confirmed menopause date.

Last period January 2010

Date of your last menstrual period
2010-01-01
Measure to
2024-01-01

Result Your stage: Late postmenopause (+2)
Menopause date (12 months after last period): January 1, 2011
Time since last period: 14 yr 0 mo
Years since menopause: 13
STRAW+10 stage: +2
Next milestone: Final stage: lasts for the rest of life
Age at the measured date: Add your age

  1. Last period: January 1, 2010; as of January 1, 2024 = 5113 days (14 yr 0 mo)
  2. Menopause date = last period + 12 months = January 1, 2011
  3. Years since menopause = 4748 ÷ 365.25 = 13
  4. STRAW+10 stage by months since last period (168): under 12 = +1a, 12–23 = +1b, 24–95 = +1c, 96+ = +2

Fourteen years on, the stage is +2, which STRAW+10 treats as lasting for the rest of life.

How it is calculated

Menopause date = last period + 12 months; stage from months since last period (under 12 = +1a, 12–23 = +1b, 24–95 = +1c, 96 or more = +2)

last period
date of the final menstrual period
months
whole calendar months from the last period to the measured date
years since menopause
days from the menopause date to the measured date ÷ 365.25

Following the National Institute on Aging definition, menopause is fixed at 12 months after the final period. STRAW+10 counts stages from the final period: +1a covers the first year, +1b the second, +1c the following three to six years, and +2 the remaining lifespan. The calculator uses 96 months as the +1c to +2 boundary, the outer end of that range.

Sources

When not to use it

  • After a hysterectomy, periods stop for surgical reasons, so the last-period date cannot stage menopause.
  • While using hormonal contraception or hormone therapy that changes bleeding, the date of the last bleed is not a reliable marker.
  • If bleeding returns after 12 months without a period, that needs medical assessment rather than a new date in a calculator.

Common mistakes

  • Entering the date of the last spotting episode a few months later rather than the last true period.
  • Treating the +1c to +2 boundary as exact when STRAW+10 gives it as a three to six year span.

Frequently asked questions

Why is menopause only confirmed after 12 months?

Periods often become irregular in the years before menopause, with gaps of several months followed by another bleed. A full 12 months without one is the point at which clinicians and the NIA treat the final period as final.

What do the STRAW+10 stages mean?

STRAW+10 is a staging system from the 2011 Stages of Reproductive Aging Workshop. Stage 0 is the final period; +1a, +1b and +1c are early postmenopause, when hormone levels are still settling and hot flushes are most common; +2 is late postmenopause, when changes such as vaginal dryness tend to become more prominent.

What age counts as early menopause?

A final period between 40 and 44 is usually called early menopause, and one before 40 is called premature menopause or primary ovarian insufficiency. The average age in the United States is about 52.

Do symptoms stop when postmenopause starts?

Not necessarily. Hot flushes and night sweats continue for several years after the final period for many people, and the median total duration reported in large studies is around seven years.

Can I use the date of a blood test instead?

No. FSH and estradiol levels fluctuate around the transition, so STRAW+10 dates the stages from the final period, not from a lab result. The calculator needs the period date.

Is the information I enter saved anywhere?

The calculation runs in your browser. Inputs may be remembered on this device for convenience, and the Reset button clears them.

Cite this tool

Using this tool in an assignment, article or report? Copy a citation, or a link for your website.

APA

Tools Directory Editorial Team. (2026, October 25). Postmenopause Calculator. Tools Directory. Retrieved October 28, 2026, from https://tools.milunir.com/health/medical-reference/postmenopause-calculator/

MLA

Tools Directory Editorial Team. “Postmenopause Calculator.” Tools Directory, 25 Oct. 2026, https://tools.milunir.com/health/medical-reference/postmenopause-calculator/. Accessed 28 Oct. 2026.

Chicago

Tools Directory Editorial Team. “Postmenopause Calculator.” Tools Directory. Last modified October 25, 2026. Accessed October 28, 2026. https://tools.milunir.com/health/medical-reference/postmenopause-calculator/.

Link<a href="https://tools.milunir.com/health/medical-reference/postmenopause-calculator/">Postmenopause Calculator – Tools Directory</a>