Menstrual Cycle Estimator

Free menstrual cycle calculator. Predict period dates based on your cycle length. Track and plan with estimated future periods.

Estimate your menstrual cycle and predict future period dates. Enter your last period start date and typical cycle length to see projected dates for upcoming cycles.

Common use cases

  • Planning around predicted period dates
  • Tracking cycle regularity
  • Travel and vacation planning
  • Medical appointment scheduling
  • General health awareness

How to use

  1. Enter the start date of your last period
  2. Enter your typical cycle length (default 28 days)
  3. View predicted dates for upcoming periods
  4. Adjust cycle length to match your pattern
  5. Track variations in your cycle

FAQ

What's a normal cycle length?

Cycles typically range from 21-35 days, with 28 days being average. Your personal pattern is what matters most.

How accurate are predictions?

Predictions are estimates based on your entered cycle length. Real cycles may vary due to many factors.

Does this predict ovulation?

For ovulation estimates, see our dedicated ovulation window estimator tool.