Period Calculator
period_calculatorRead-onlyIdempotent
Predict your next six periods from the date your last one started and your cycle length, with ovulation days and fertile windows on the same calendar. Web page: https://calcbright.com/period-calculator
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| date | No | First day of your last period (YYYY-MM-DD) | 2026-10-01 |
| cycle | No | Average cycle length (days) From the first day of one period to the first day of the next – 28 on average. | |
| length | No | Period length (days) |