Next period (est.)
May 27, 2026
Ends around
May 31, 2026
Ovulation (est.)
May 13, 2026
Fertile window
May 8, 2026–May 14, 2026
How the estimate works
The next period is estimated by adding your average cycle length to your last start date. Ovulation is commonly estimated as ~14 days before the next period.
Important note
Cycles vary due to stress, sleep, travel, training, and health changes. If you have irregular cycles or concerning symptoms, consult a clinician.
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After you get your result, compare a few scenarios or explore related tools.
This calculator estimates your next period date by adding your average cycle length to your last period start date. It also estimates ovulation as about 14 days before the next period.
The fertile window is commonly estimated as the 5 days before ovulation and the day of ovulation.
For general health context, you can also check body metrics using the BMI Calculator or nutrition planning numbers using the TDEE Calculator.
Example: last period started on March 1 with a 28-day average cycle.
Next period estimate: March 29
Ovulation estimate: about 14 days before (around March 15)
Real timing can vary month to month. Use the dates as a planning estimate.
If you’re tracking trends or planning nutrition around training and daily routine, these tools pair well:
Browse more tools in this category or return to the ClearCalculate homepage.