Ovulation Calculator
Free online Ovulation Calculator.
Calculator
How to Use
- Enter the required values
- Click Calculate to see the result
- Review the detailed output
Formula
Ovulation Day = Cycle Length - 14 days. Fertile Window = Ovulation Day - 5 days to Ovulation Day. Based on typical luteal phase of 14 days.
Example Calculations
28-Day Cycle
Input: Last period: October 1, Cycle length: 28 days
Result: Ovulation: October 15, Fertile: Oct 10-15
32-Day Cycle
Input: Last period: October 1, Cycle length: 32 days
Result: Ovulation: October 19, Fertile: Oct 14-19
Short Cycle
Input: Last period: October 1, Cycle length: 24 days
Result: Ovulation: October 11, Fertile: Oct 6-11
About This Calculator
Free online ovulation calculator. Calculate instantly in your browser with our easy-to-use tool. No sign-up required.
Our ovulation calculator is free, easy to use, and provides instant results. All calculations are performed in your browser for privacy and speed.
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Frequently Asked Questions
When does ovulation occur?
About 14 days before next period. Day 14 for 28-day cycle, day 18 for 32-day cycle.
How to tell when ovulating?
Changes in cervical mucus, basal body temperature rise, mild pelvic pain. OPKs detect LH surge.
What is the fertile window?
6-day period ending on ovulation day. Sperm survives up to 5 days in the reproductive tract.
Ovulate more than once?
Typically once per cycle, but sometimes two eggs release within 24 hours (fraternal twins).
Stress and ovulation?
Significant stress can delay or suppress ovulation. Exercise, meditation, and sleep help regulate cycles.