Period and Ovulation Calculator

A period tracker only predicts your next period. This calculator also returns your ovulation day, fertile window, and second upcoming period, all from the same LMP input. It serves both menstrual planning and conception use cases.

For consistent 26-32 day cycles, predictions are typically within 1-3 days. The luteal phase is biologically stable at 14 days, but the follicular phase can shift due to stress, illness, or weight changes. After 3-6 tracked cycles your average becomes more reliable.

Peak fertility falls in the 2 to 3 days immediately before ovulation. On a 28-day cycle that is typically cycle days 12, 13, and 14. Sperm can survive up to 5 days, so intercourse from day 9 onward gives a reasonable conception chance.

Period length affects only the period-end date prediction, not ovulation. Periods of 2 to 7 days are within the normal range. If your bleeding is consistently under 2 days or over 8 days, consult your healthcare provider.

Yes, up to 45 days. For a 35-day cycle, ovulation moves to around day 21 (35 minus 14). Cycles longer than 35 days may indicate anovulation or PCOS, in which case the irregular period ovulation calculator gives a more honest prediction window. This tool is for educational planning and is not medical advice.

A period 5 to 7 days late after a typical cycle warrants a pregnancy test (most home tests are reliable from 14 days past ovulation). Stress, travel, or illness can also delay periods. If you have irregular cycles longer than 35 days for three or more consecutive months, consult a healthcare provider.

Yes, the Period and Ovulation Calculator is fully embeddable. Tap "Embed" above to configure appearance and copy the code. It is free to use, works on any platform (HTML, WordPress, CMS), and adjusts to any screen size automatically. Visit calculory.com/services/embed-calculators for the complete guide.