App description

When calculating, first check if your computer date is correct. If not, please proofread the time, otherwise the calculation is not possible.

If your menstrual cycle is not 28 days, please set your cycle and calculate!

The safe contraceptive period calculation is for reference only. Due to individual differences, this calculator is for reference only! Since the safety cycle of people is different, it is not absolutely reliable.

Usage example

Start time of last menstruation: October 7, 2019

Minimum menstrual cycle: 28

Longest menstrual cycle: 28

Click "Calculate" to output the result.