PCOS Period Predictor

Why Regular Period Calculators Don't Work for PCOS

Standard period calculators assume a fixed cycle length (usually 28 days). But with PCOS, cycles can range from 30 to 90+ days — and vary significantly month to month. A tool that says "your next period is in 28 days" is useless when your cycles are 35-60 days.

This predictor is different. It uses your actual cycle history to calculate a prediction window — an earliest, latest, and most likely date — based on your real patterns, not a textbook average.

How This Predictor Works

1. Enter the first day of your last 3-6 periods
2. We calculate the length of each cycle (days between periods)
3. Your prediction window = from your shortest cycle to your longest cycle from the last period date
4. The "most likely" date is based on your average cycle length

The more periods you track, the narrower and more accurate your prediction window becomes.

When to See a Doctor About Your Period

• No period for 90+ days (amenorrhea)
• Fewer than 8 periods per year
• Very heavy bleeding lasting more than 7 days
• Sudden change in your pattern after years of regularity
• Severe pain that interferes with daily life

Related Tools & Resources

• Ovulation Calculator — estimate your fertile window
• PCOS Type Quiz — find out which type of PCOS you have
• HOMA-IR Calculator — check your insulin resistance
• PCOS and Irregular Periods: Causes & What to Do
• PCOS and Fertility
• PCOS Treatment Options
• PCOS and Insulin Resistance

Important Disclaimer

This tool provides estimates based on your cycle history. With PCOS, periods can remain unpredictable regardless of past patterns. This is not a pregnancy test or medical diagnosis. If you're concerned about a missed period, take a pregnancy test and consult your healthcare provider.