What is Ovulation Calculator?
An ovulation calculator predicts the release of a mature egg from the ovary, pinpointing the 6-day fertile window (the 5 days leading up to ovulation plus the day of ovulation itself).
How to Use This Calculator
- Enter the calendar date of the first day of your last period.
- Specify your typical cycle duration (e.g. 28 days).
- Identify your highest probability conception days.
The Mathematical Formula & Variables
Ovulation Date = LMP + Cycle Length - 14 days; Fertile Window = Days -5 to Day of Ovulation
Variables Definition
| Symbol / Variable | Name | Description |
|---|---|---|
14 Days |
Luteal Phase | The biologically constant duration between ovulation and subsequent menstruation. |
Step-by-Step Worked Example
Scenario: LMP started February 15 with a regular 28-day cycle.
- Next period starts: February 15 + 28 days = March 15.
- Subtract 14 days luteal duration: March 15 - 14 days = March 1.
- Fertile window covers February 24 through March 1.
Result: Peak Ovulation = March 1
Frequently Asked Questions
How long can sperm survive inside the female reproductive tract?
Healthy sperm can survive up to 5 days in fertile cervical mucus, which is why intercourse several days prior to ovulation can successfully result in pregnancy.