Ovulation Date for a 30-Day Cycle
With a 30-day cycle, ovulation generally happens around day 16, placing the fertile window approximately on days 13–18.
How to use this tool
- Enter first day of last period and cycle length in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your estimated ovulation and the full breakdown beneath it.
A slightly longer cycle shifts your fertile window later — find your exact dates with this ovulation calculator.
Frequently asked questions
- How accurate is this ovulation calculator?
- Cycle lengths vary, and ovulation can shift by several days due to stress, illness, or hormonal changes. Use this as a guide, not a certainty. Ovulation predictor kits give same-day confirmation.
- When is the best time to try to conceive?
- The 2–3 days just before ovulation are statistically the most fertile, as sperm can survive several days in the reproductive tract.