Next Period Predictor
Predict your next period start date from your last period and cycle length.
Your result
Predictions assume a regular cycle. Irregular cycles, stress, illness and breastfeeding can all shift timing.
Medical disclaimer: This tool is for education and is not medical advice. Read more.
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Frequently asked questions
What does the Next Period Predictor do?
Predict your next period start date from your last period and cycle length. Enter your values and the result and chart update instantly.
How accurate is it?
It uses published, widely used formulas. Results are estimates for education and planning, not a diagnosis. Talk to a qualified clinician about decisions affecting your health.
Is my information stored or shared?
No. All calculations run in your browser and nothing you type is sent to a server or saved.
What can I search to find this tool?
People find it by searching for: when is my next period; period prediction; expected period date.