How to tell when you're ovulating

1. Calendar estimate: when is it likely?

Ovulation usually happens about two weeks before your next period. If you know your typical cycle length, you can estimate it by counting back from your expected next period. It's quick, but because the days before ovulation vary from cycle to cycle, it's only an estimate.

2. LH tests: is it coming soon?

Ovulation tests detect a surge of luteinizing hormone (LH) in urine. The surge comes shortly before ovulation, so a positive test means ovulation is likely in the next day or so. Start testing a few days before your estimated fertile window, ideally at the same time each day.

LH tests can be harder to read for some people, including those with PCOS, where LH may be elevated for longer.

3. Basal body temperature: did it happen?

After ovulation, progesterone raises your resting temperature slightly and keeps it raised until your next period. Take your temperature right after waking, before getting up, at about the same time each day.

A common way to read the chart is the three-over-six rule: three temperatures in a row that are all higher than the previous six, with the third clearly higher. Ovulation most likely happened on the last low day. Temperature confirms ovulation after the fact, so it's most useful for learning your pattern over several cycles.

Putting them together

• Use the calendar to know when to start LH testing.
• Use a positive LH test to know ovulation is close.
• Use the temperature rise to confirm it happened, and to learn how long your luteal phase is.

LunWise does this for you: log LH tests or temperatures, or import temperatures from a wearable, and it confirms ovulation and uses it to predict your next period more precisely.