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Ovulation Signs & Your Fertile Window
Ovulation is the most important — and most misunderstood — moment of your cycle. Here's how to recognise it from your body's own signals, no guesswork required.
Whether you're trying to conceive, trying to avoid it, or just want to understand your body, ovulation is the event everything else revolves around. The good news: your body broadcasts several reliable signals — once you know what to look for.
First, bust the "day 14" myth
You've probably heard that everyone ovulates on day 14. That's an average, not a rule. Ovulation actually tends to happen about 12 to 16 days before your next period starts, counting backwards. For someone with a 28-day cycle that lands near day 14 — but for a 32-day cycle it's closer to day 18, and for a 24-day cycle, around day 10. This is exactly why tracking your cycle beats relying on a textbook number.
The three main signs of ovulation
1. Cervical mucus changes
This is the single most useful natural sign. In the days leading up to ovulation, rising estrogen makes cervical mucus increase and turn clear, slippery and stretchy — often compared to raw egg white. That "egg-white" texture signals your most fertile days. After ovulation it becomes thicker, cloudier and drier.
2. Basal body temperature (BBT)
Your resting body temperature rises slightly — about 0.3–0.5°C — after ovulation, thanks to progesterone. Measured first thing each morning before getting up, a sustained shift confirms ovulation has happened. The catch: BBT tells you ovulation has already occurred, so it's better for spotting your pattern over time than for catching the window in advance.
3. Ovulation pain and other signals
Some people feel a brief, one-sided twinge low in the pelvis called mittelschmerz. Others notice a higher libido, mild breast tenderness, or a little spotting around ovulation. These are supporting clues rather than proof on their own.
Want more certainty?
Ovulation predictor kits (OPKs) detect the surge in luteinising hormone (LH) that happens 24–36 hours before ovulation — useful if you're timing for conception and want advance notice that the window is opening.
How to find your fertile window
Because sperm can survive up to about five days in fertile cervical mucus, your fertile window is roughly the five days before ovulation plus ovulation day — about six days total. The two days before ovulation are typically the most fertile. To estimate it:
- Track your cycle length for a few months (here's how to track your period).
- Subtract 12–16 days from your expected next period to estimate ovulation.
- Watch for egg-white cervical mucus to confirm the window is opening.
Trying to avoid pregnancy?
Fertility awareness can be used to avoid conception too, but it requires careful, consistent tracking and a wider safety margin — and it is less forgiving with irregular cycles. On its own it is not as reliable as dedicated contraception, so talk to a clinician about what fits your situation.
If your ovulation signs are hard to read or your cycle is unpredictable, it may be worth understanding why — see our guide to irregular periods and their causes, and how ovulation fits into the wider menstrual cycle phases.
Frequently asked questions
How do I know when I'm ovulating?
Watch for clear, stretchy egg-white cervical mucus, a small sustained BBT rise just after, and sometimes a one-sided twinge. OPKs detect the hormone surge that comes just before.
When exactly is my fertile window?
Roughly the five days before ovulation plus ovulation day. Ovulation itself is usually 12–16 days before your next period.
Can I get pregnant outside my fertile window?
It's much less likely but not impossible — particularly with irregular cycles, where ovulation timing can shift. Tracking estimates fertility; it isn't reliable contraception by itself.