Luteal Phase Calculator

Find out when your luteal phase starts and how long it lasts — the key to understanding PMS and progesterone health.

Ovulation date (or estimated)

First day of next period

What is the luteal phase?

The luteal phase is the second half of your menstrual cycle, beginning after ovulation and ending when your next period starts. It typically lasts 10–16 days and is driven by progesterone production from the corpus luteum.

A luteal phase shorter than 10 days (luteal phase defect) may make it harder to sustain a pregnancy. Symptoms like bloating, mood changes, and breast tenderness during this phase are associated with PMS and PMDD.

Note: This calculator provides estimates only. If you have concerns about your cycle, consult a healthcare provider.