Understand your body's natural rhythm. Predict your next period, find your most fertile days, and plan ahead with confidence.
Tracking your menstrual cycle is key to understanding your reproductive health. Follow these simple steps to get accurate predictions for your next period and ovulation:
Enter the first day of your last period using the date picker.
Input your average cycle length (usually 28 days) and period duration.
Click the button to reveal your next period date, ovulation day, and fertile window.
A typical menstrual cycle lasts 28 days, but anything from 21 to 35 days is considered normal and healthy. Your cycle officially begins on the first day of your period (when bleeding starts) and ends the day before your next period begins.
The cycle consists of four distinct phases, each driven by hormonal changes.
The womb lining sheds through the vagina, resulting in your period. Estrogen and progesterone levels are low.
Overlapping with menstruation, the pituitary gland signals ovaries to produce follicles. One matures into an egg, and estrogen rises to thicken the uterine lining.
A surge in luteinizing hormone (LH) causes the release of the mature egg. This is your peak fertility time. The egg survives for 12-24 hours.
The follicle transforms into the corpus luteum, releasing progesterone to support potential pregnancy. If no fertilization occurs, hormones drop, and the cycle restarts.
If you are trying to conceive, timing is everything. Sperm can survive in the female body for up to 5 days, while an egg only survives for 12-24 hours after ovulation.
You are most fertile during the 5 days leading up to ovulation and the day of ovulation itself. This "6-day window" maximizes the chance of sperm meeting the egg.
No. While 28 days is the average, a "normal" cycle can range anywhere from 21 to 35 days. Cycles can also vary slightly from month to month due to stress, diet, or travel.
No. This calculator is an estimation tool based on averages. It should not be used as a primary method of contraception (birth control). Cycle dates can shift unpredictably.
The calculator predicts ovulation 14 days before your next expected period, which is the standard medical average. However, actual ovulation can vary. For precise tracking, consider using ovulation test kits or tracking basal body temperature.
If your cycle length varies significantly (e.g., 25 days one month, 35 the next), enter the average length of your last 3 cycles for the best estimate. Consult a doctor if you experience frequent irregularity.
