Period Calculator
Calculate when your next period is expected to start based on your cycle length.
Next expected period
Sunday, August 2, 2026
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Period Calculator: Next Bleed Start (Estimate)
Estimate when your next period may start from the first day of your last bleed and your average cycle length in days. The result is one calendar date for planning, not a diagnosis or contraception tool.
How to use
Enter Last period start date (day 1 of bleeding) and Average cycle length (days). Next expected period = last start date plus that many days. Use the average of your last three full cycles when you can; a single unusual month can skew the guess.
Example
Last period started 3 June with a 28-day average suggests the next start around 1 July. Stress, illness, or hormonal shifts can move the real date by a few days either way.
Tips
Log start dates to keep your average current. This page does not predict ovulation or fertile days. For a fertile-window estimate, use the ovulation calculator with the same cycle data. See a clinician if cycles are very irregular, suddenly change, or cause worrying symptoms.