What are the signs of ovulation?

Signs of ovulation are thin, slippery, stretchy cervical mucus (ACOG) and a small rise in your resting temperature (ACOG). Some women also get pain on one side of the tummy (NHS). A positive ovulation test suggests ovulation in the next 24 to 48 hours, and a temperature rise only confirms it afterwards (ACOG).

By Hossam Hamouda, developer of Period Calc · Last updated: 25 October 2026

Predictions are estimates, not medical advice or a diagnosis, and not a method of contraception.

When does ovulation happen?

Ovulation usually happens about 14 days before your next period (NHS); in most women it is 10 to 16 days before (NHS). The cycle day when ovulation falls depends on your cycle length. Sex from 5 days before ovulation up to 1 day after it can lead to pregnancy (ACOG). The ovulation calculator estimates that window from your dates. Already pregnant? Count back to the conception date with the conception date calculator.

Cervical mucus

Cervical mucus is the fluid made by your cervix, the lower end of the womb. Just before ovulation there is noticeably more of it, and it becomes thin and slippery (ACOG). The NHS says that around ovulation vaginal secretions (discharge) become thinner and stretchy, “a bit like raw egg white” (NHS). It adds that discharge is often clearer and wetter around ovulation, and may be easier to notice (NHS).

An ACOG expert article says the mucus peaks 1 to 2 days before ovulation. ACOG says that just after ovulation there is less of it and it becomes thicker and less noticeable (ACOG). Medicines, hygiene products, douching, sex, breastfeeding and a pelvic exam with lubricant can all change how it looks (ACOG).

Body temperature

Basal body temperature is your temperature at rest. In most women it rises slightly at ovulation, by 0.5 to 1 °F, and stays high until the end of the cycle (ACOG). In degrees Celsius that is about 0.3 to 0.6 °C (our conversion of ACOG’s figure). ACOG says to take it every morning, right after waking and before anything else, including getting out of bed, eating or drinking (ACOG). A fever may make the method unreliable (ACOG). ACOG describes charting your temperature for two or three cycles (ACOG).

How do ovulation tests work?

An ovulation test checks your urine for a rise in luteinising hormone (LH), a hormone whose surge triggers the release of an egg. A positive result suggests that ovulation will happen in the next 24 to 48 hours (ACOG).

Ovulation pain

Some women get ovulation pain, which the NHS says often feels like a dull pain or sharp sudden twinges on one side of the tummy. It often lasts from a few minutes to 1 or 2 days and comes about 14 days before a period (NHS). Ovulation pain may come with a little vaginal bleeding or discharge, and it is usually short-lived and nothing to worry about (NHS). Other conditions, including an ectopic pregnancy (a pregnancy outside the womb), can cause a similar pain (NHS): see when to ask for help. If you may be pregnant, read about a late period and use the pregnancy test date calculator.

How reliable is each sign?

• Mucus. An ACOG expert article says that of the ways to spot ovulation yourself, watching cervical mucus tends to be the most reliable. It also says no method is foolproof for working out your fertile days.
• Temperature. A chart confirms ovulation but cannot predict it (ACOG). ACOG places the most fertile days 2 to 3 days before the rise (ACOG), so the rise only tells you in hindsight (our reading of ACOG’s two statements). A temperature rise does not show that any day is free of the chance of pregnancy.
• Ovulation tests. An ACOG expert article warns that ovulation tests do not work for everybody and that their results are not always accurate.

Fertility awareness-based methods track your body’s natural signs to find when you are most likely to get pregnant (ACOG).

The NHS says it does not officially recommend any of the apps and fertility monitors made to track fertile days (NHS). Period Calc predicts only from your period dates and measures nothing in your body.

The signs of ovulation are not a method of contraception. None of them can tell you that a day carries no chance of pregnancy. The WHO calls fertility awareness-based methods less reliable than the other family planning methods it lists (WHO).

When to ask for help

If you are trying to get pregnant, the WHO defines infertility as no pregnancy after 12 months or more of regular unprotected sex (WHO). ACOG recommends an evaluation after 1 year of trying, or after 6 months if you are older than 35. It says to talk to your doctor now if you are older than 40 (ACOG). The NHS says to see a doctor after a year, and sooner if you are 36 or over (NHS).

Talk to a doctor sooner if:

• you have irregular periods and find it hard to get pregnant (NHS). An ACOG expert article says highly irregular periods may mean you are not ovulating;
• you bleed between periods (NHS);
• you have tummy pain that does not get better with painkillers or keeps coming back. The NHS asks for urgent medical advice if the pain is severe and painkillers have not helped. It asks for the same if the pain keeps coming back or you think you may be pregnant (NHS). Use the emergency or urgent medical service of your country.