Your Cycle Information
Typical: 21-35 days
Typical: 12-16 days
Cycle Calendar
Key Dates This Cycle
Maximizing Fertility
Best Days to Conceive
- • 1-2 days before ovulation (highest chance)
- • Day of ovulation
- • Regular intercourse during fertile window
- • Every 1-2 days during fertile period
Signs of Ovulation
- • Clear, stretchy cervical mucus (egg white)
- • Slight rise in basal body temperature
- • Mild pelvic pain or cramping
- • Increased libido
- • Positive ovulation predictor kit (OPK)
Important Note
This calculator provides estimates based on average cycle patterns. Actual ovulation can vary. For conception planning, consider using ovulation predictor kits or tracking basal body temperature. This tool should not be used as a reliable form of contraception. Consult a healthcare provider for personalized fertility advice.
Your Fertility Window
Ovulation Date
Wed, Oct 21
Today!
Fertile Window
Fri, Oct 16 - Thu, Oct 22
6 days
You are currently in your fertile window!
Cycle Scenarios
Explore how changes affect your results
Fertility Tips
Based on your results
Your Cycle Pattern
With a 28-day cycle and 14-day luteal phase, you likely ovulate around cycle day 14. You are currently in your fertile window!
Optimal Timing
The highest conception chance is 1-2 days before ovulation. Regular intercourse every 1-2 days during the fertile window maximizes chances.
Ovulation Signs
Look for ovulation signs: egg-white cervical mucus, slight temperature rise (0.5-1°F after ovulation), mild pelvic pain, and positive OPK tests.
Frequently Asked Questions
When do I ovulate?
Ovulation typically occurs 12-16 days before your next period (luteal phase). For a 28-day cycle, this is usually around day 14. However, cycle lengths vary, so tracking is important. Signs include increased cervical mucus, slight temperature rise, and mild pelvic pain.
What is the fertile window?
The fertile window spans about 6 days: the 5 days before ovulation plus ovulation day. Sperm can survive up to 5 days in the reproductive tract, while the egg only survives 12-24 hours. The highest chance of conception is 1-2 days before ovulation.
How accurate is ovulation prediction?
Calendar-based predictions provide estimates but aren't precise. Actual ovulation can vary by several days. For more accuracy, combine with ovulation predictor kits (OPKs), basal body temperature tracking, or cervical mucus monitoring.
What affects ovulation timing?
Many factors can shift ovulation: stress, illness, travel, weight changes, exercise, medications, and hormonal imbalances. The follicular phase (before ovulation) varies most; the luteal phase (after) is typically consistent at 12-16 days.
Can I get pregnant outside the fertile window?
Pregnancy is extremely unlikely outside the fertile window since the egg only survives 12-24 hours. However, sperm can survive up to 5 days, so intercourse before ovulation can still result in pregnancy. No calendar method is 100% reliable for contraception.
How this works
Estimates the fertile window as cycle_length − 14 days from the first day of the last period, with a 5-day window before and 1 day after ovulation.
What this tool can’t do
- Cycle length and ovulation day vary; track basal body temperature or LH surge for higher accuracy when trying to conceive.
When to consult a professional
Talk to a licensed healthcare provider before using the output of this tool to make a medical decision, especially if you have an underlying condition, are pregnant, or are on medication that affects metabolism or fluid balance.
Sources
- [1]Centers for Disease Control and Prevention (CDC)Official sourcecdc.govAccessed Apr 21, 2026
- [2]National Institutes of Health (NIH)Official sourcenih.govAccessed Apr 21, 2026
Full-stack software engineer specializing in embedded systems, web architecture, and AI/ML. Founder of Practical Web Tools. Built the gesture-controlled drone IP acquired by KD Interactive (Aura Drone, sold on Amazon).