period tools

Missed Period Calculator

See exactly how many days since your expected period, and learn the most likely reasons periods are skipped or delayed.

Pick the date your most recent period started.

21 days45 days

Days from one period's first day to the next. Most cycles are 21–35 days.

1 day10 days

How many days bleeding usually lasts.

Pick the first day of your last period to see your next 6 cycles.

Missed period versus late period

There’s no official line between “late” and “missed”. On this page we use:

  • Late: 1–6 days past expected date. Usually normal variation.
  • Missed: 7+ days past expected date. If pregnancy is possible and you haven’t tested yet, test now. You can test from the first day your period is late.
  • Skipped: the entire cycle goes by without a period — typically 30+ days late by the time you’re confident.
  • Amenorrhoea: three or more skipped periods in a row. Always worth a provider visit.

Wondering if it’s pregnancy?

Read PMS vs pregnancy: 9 ways to tell the difference for the early signs, why they overlap with PMS, and when to take a test.

Common causes of a missed period

The most common, beyond pregnancy:

  • Stress. Strong stress or grief affects the brain chemistry that controls ovulation. Periods can vanish for a month or two and resume on their own.
  • Significant weight change. Sudden weight loss (especially with calorie restriction) often pauses cycles. Major weight gain can have the same effect through hormonal shifts.
  • Intense exercise. Athletes and people who train hard sometimes stop having periods entirely (“hypothalamic amenorrhoea”).
  • Hormonal contraception. The pill, hormonal IUDs, implants, and injections can make periods lighter, irregular, or absent — often by design.
  • PCOS. Polycystic ovary syndrome (now also called PMOS) is one of the most common reasons for irregular or missed periods.
  • Thyroid imbalance. Both overactive and underactive thyroid affect periods.
  • Perimenopause. Cycles become irregular, then stop, in the years before menopause (average age 51).

Frequently asked questions

What counts as a missed period?
There’s no single medical cut-off for a ‘missed’ period. Pregnancy tests count a period as missed from the day it was due. Skipping one period now and then is common and usually not a worry. Three or more missed periods in a row (amenorrhoea) deserves a conversation with your provider.
Can I have a missed period and not be pregnant?
Yes. Stress, illness, big weight changes, intense exercise, hormonal contraception transitions, PCOS, thyroid imbalance, perimenopause, and breastfeeding all cause missed periods. Pregnancy is just the most common reason in reproductive-age people with a possible exposure — but it’s far from the only one.
How many missed periods is too many?
If you miss three periods in a row without an obvious reason, see a healthcare provider. There are usually treatable causes, and a few of them — such as thyroid problems or persistent ovulation issues — are easier to manage the earlier they’re spotted.
What should I do after a missed period?
If pregnancy is possible, take a home pregnancy test. If it’s negative and your period still hasn’t arrived a few days later, test again. If the second test is also negative, check with your provider. If pregnancy isn’t a factor, watch for accompanying symptoms (fatigue, weight changes, mood shifts, hair changes) and bring those up at your next visit.
Is a missed period dangerous?
A single missed period rarely is. Long-term amenorrhoea can affect bone density and fertility — which is one reason providers want to find the underlying cause when periods stop for several months. Most causes are manageable once identified.

Related tools

Sources

Checked against the following public guidance on September 26, 2026. Advice can differ between countries; your doctor, nurse or midwife can apply it to you.

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