🌼 Period Calculator

Enter the first day of your last period and cycle length to predict the next 6 periods, the ovulation day and fertile window. Personal health reference, local, no upload.

❓ Frequently asked questions

How is ovulation estimated?

As cycle length minus 14 (the luteal phase is usually ~14 days).

What is the fertile window?

About 5 days before to 1 day after ovulation - the higher-conception window.

Is it accurate?

A reference for regular cycles only; real timing varies with stress and health.

📚 How to use

Knowing your cycle helps with planning or trying to conceive.

Steps

  1. Enter the first day of your last period and cycle length.
  2. Click "Predict".
  3. See upcoming periods, ovulation and fertile window.
💡 This is a health reference, not medical advice.