📅 Luteal Phase Calculator
Calculate the length of your luteal phase, the time between ovulation and the start of your next period.
What the luteal phase is
The luteal phase is the second half of the menstrual cycle, running from the day of ovulation until the first day of the next period. Unlike the first half of the cycle, which can vary in length from person to person, the luteal phase tends to be fairly consistent, typically lasting between 11 and 17 days, with 14 days being the most common average.
How this calculator works
Enter your total average cycle length and the cycle day on which you ovulate (day 1 is the first day of your period). Subtracting the ovulation day from the total cycle length gives the luteal phase length, since ovulation marks the transition point between the two phases of the cycle.
A consistently short luteal phase is sometimes discussed in fertility research, but a single cycle’s measurement can vary and does not by itself indicate any condition. This calculator is for general educational purposes only and is not a substitute for advice from a healthcare provider.