Assess Your Luteal Phase
A healthy luteal phase typically lasts 10–16 days after ovulation. Track your cycle to identify implantation timing and optimal testing windows.
Use positive LH test, BBT shift, or ultrasound to confirm.
Provides exact luteal phase length if known.
Evaluate if testing timing is optimal.
How to Use This Calculator
Track ovulation accurately
Use LH tests, basal body temperature, or ultrasound to identify the ovulatory day.
Note the next period start
Recording the following cycle start allows precise luteal length calculation.
Use results to guide testing
Plan pregnancy tests 12–14 days after ovulation and explore evaluation if the luteal phase is consistently short.
Formula
Luteal phase length = Next period start − Ovulation date
Implantation window = Ovulation + 6 to +10 days
Optimal pregnancy test = Ovulation + 12 days
Short luteal phase is typically <10 days; long is >16 days.
Full Description
The luteal phase spans from ovulation to the onset of menstruation, driven by progesterone to prepare the endometrium for implantation. Short luteal phases may hinder implantation and are sometimes linked to luteal phase defects, though the concept remains debated. Tracking length over several cycles helps identify patterns and decide if evaluation or progesterone support is warranted.
Frequently Asked Questions
How many cycles should I track?
Track at least three cycles to understand your typical luteal length before drawing conclusions.
Can stress shorten the luteal phase?
Severe stress can disrupt hormone balance. Persistent short luteal phases warrant medical evaluation.
Is spotting a sign of luteal phase defect?
Mid-luteal spotting may occur for various reasons. Combine observations with cycle length when discussing with your provider.
Does progesterone supplementation lengthen the luteal phase?
Progesterone support can extend the luteal phase and improve endometrial receptivity in certain fertility treatments.