Free family guide · Trying to conceive

When do you ovulate?

OWH says there are about 6 days in each menstrual cycle when you can get pregnant, called the fertile window.[1]

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Sources on this page: OWH; ACOG

This page shares what health organizations say. It is not medical advice. It is general information. Talk to your doctor, midwife or pediatrician about your own situation.

In an emergency, call 911.

Your cycle and ovulation

OWH says the average cycle is 28 days, and normal cycles range from 21 to 35 days.[2] It says a period comes 14 to 16 days after ovulation unless pregnancy occurs.[2]

OWH says sperm can survive up to about 3 days.[2]

It says fertile windows differ between women, and from month to month in the same woman.[1]

Three ways to find your fertile days

OWH describes three methods:[2]

  • body temperature, where you are most fertile from about 2 to 3 days before the temperature peak until 12 to 24 hours after ovulation;[2]
  • the calendar, where you subtract 18 from your shortest cycle and 11 from your longest to mark the start and end of the window;[2]
  • cervical mucus, where you are most fertile at the first sign of wetness after your period.[2]

Sources differ

Sources describe body temperature tracking differently:[2][3]

  • OWH says that with body temperature tracking, you are most fertile from about 2 to 3 days before the temperature peak until 12 to 24 hours after ovulation.[2]
  • ACOG says basal body temperature can confirm ovulation but cannot predict it.[3]

ACOG says cervical mucus becomes thin, slippery and stretchy just before ovulation.[3]

ACOG says a positive LH urine test suggests ovulation in the next 24 to 48 hours.[3]

What tracking cannot do

OWH says its own ovulation calculator gives an estimate of the fertile window and is not a guarantee of pregnancy or of birth control.[1]

When to see a doctor

OWH says to see a doctor after 1 year of frequent sex without birth control if you are under 35.[2] It says to see a doctor after 6 months if you are 35 or older.[2]

Questions families ask

Is the fertile window before or after my period?

OWH says a period comes 14 to 16 days after ovulation unless pregnancy occurs, so ovulation happens before the period.[2]

What if my periods are irregular?

It says fertile windows differ between women, and from month to month in the same woman.[1] OWH says the average cycle is 28 days, and normal cycles range from 21 to 35 days.[2]

How long can sperm live?

OWH says sperm can survive up to about 3 days.[2]

Free from UpOnly Learning. Written for families of every faith. No outside ads and no affiliate links. Every fact on this page comes from the sources listed below. How we source and review these pages

Updated 2026-10-24: first published.

Sources

All sources were opened and checked on the date shown.

  1. Office on Women's Health (HHS). Ovulation calculator. Checked October 24, 2026.
  2. Office on Women's Health (HHS). Trying to conceive. Checked October 24, 2026.
  3. American College of Obstetricians and Gynecologists. Evaluating Infertility. Checked October 24, 2026.