period tools

Late Period Calculator

Find out exactly how late your period is. The calculator below shows the expected date based on your cycle and counts the days since that date — so you can see at a glance whether you’re a day off or a week behind.

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 days10 days

How many days bleeding usually lasts.

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

What counts as “late”

  • 1–3 days late: well within normal variation, even for someone with regular cycles. Don’t panic.
  • 4–7 days late: still common. Stress, travel, sleep changes, illness, or new exercise routines can shift a cycle this much.
  • 8–14 days late: consider a home pregnancy test if pregnancy is possible. If you keep getting negatives but your period still hasn’t arrived, follow up with your provider.
  • 14+ days late or missed entirely: three skipped periods in a row is the medical definition of amenorrhoea and is worth checking out.

Common reasons a period is late

  • Pregnancy
  • High stress or recent emotional shock
  • Recent illness or infection
  • Significant weight loss or weight gain
  • Intense or new exercise routine
  • Recently started or stopped hormonal birth control
  • Polycystic ovary syndrome (PCOS)
  • Thyroid imbalance (over- or underactive)
  • Perimenopause
  • Breastfeeding

PMS or pregnancy?

The symptom overlap is real and confusing. Our guide on PMS vs pregnancy: 9 ways to tell the difference walks through nine specific signs that reliably separate the two — including implantation bleeding patterns, BBT trajectory, and the single most diagnostic rule (symptom resolution timing).

When to take a pregnancy test

Most home pregnancy tests are designed to be accurate from the first day of a missed period — about 14 days after ovulation. More sensitive tests can detect pregnancy a few days earlier, but very early tests have higher false-negative rates. If your first test comes back negative and your period still hasn’t arrived another week later, test again before assuming you’re not pregnant.

Frequently asked questions

How many days late is too late?
A period one to three days late is well within normal variation. Beyond about seven days late, most people start considering pregnancy or another cause. If your period is more than a week late and pregnancy is possible, taking a home pregnancy test gives you a clearer answer.
Can stress make my period late?
Yes. High stress affects the hypothalamus, which controls the hormones that drive ovulation. Significant emotional stress, sleep loss, or travel can delay or skip a period entirely. One stress-delayed cycle is normal; recurring late or missed periods after stress is worth a conversation with your healthcare provider.
What else delays periods?
Common reasons besides pregnancy: recent illness, intense exercise, big weight changes, polycystic ovary syndrome (PCOS), thyroid imbalance, coming off hormonal contraception, perimenopause, breastfeeding, or recently postpartum. Some medications (including steroids and chemotherapy drugs) also affect cycles.
When should I take a pregnancy test?
Most home pregnancy tests can detect pregnancy from the first day of a missed period, and the more sensitive tests work a few days earlier. If you test negative but your period still hasn’t arrived after another week, test again — hCG levels rise rapidly in early pregnancy.
When should I see a doctor about a late period?
If your period is consistently more than seven to ten days late month after month, if you have other symptoms (pelvic pain, unusual discharge, severe fatigue), or if you’ve missed three periods in a row without a clear reason, please book a visit. There are many treatable causes, and getting an answer early is always better.

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