Next Period Date & Cycle Predictor
Predict the start date of your next period and identify the key phases of your cycle.
Your Cycle Details
The first day of your last period.
Estimated Next Period Start
—
This is the projected start date.
Key Dates
| Predicted Ovulation: | — |
|---|---|
| Fertile Window (Approx.): | — |
How Your Cycle is Predicted
The **Period Calculator** estimates your cycle based on the assumption of a typical **14-day Luteal Phase** (the time between ovulation and the start of your next period). By knowing the length of your cycle and the date of your last period, we can project future dates.
Calculation Method
- **Next Period:** $\text{LMP} + \text{Cycle Length days}$
- **Ovulation:** $\text{Next Period} – 14 \text{ days}$
Key Terms (FAQ)
How reliable is this period prediction?
This prediction is highly accurate for individuals with **regular cycles**. If your cycle length varies by more than a few days each month, the prediction will be less accurate. Lifestyle changes, stress, or illness can also delay or advance your predicted period.
What is the “Luteal Phase”?
The Luteal Phase is the second half of the menstrual cycle, starting after ovulation and lasting until the next period begins. It is the most consistent phase, typically lasting 12 to 16 days (we use 14 days for prediction).