At Pregnancy Chance Calculator, our goal is simple: to build the most trustworthy fertility tools on the web. Unlike apps that rely on simple ovulation tracking—a method shown to be pretty unreliable—our approach is different. We build our calculators on a foundation of three core principles:
- Continuous Improvement: We constantly refine our models based on new research and, most importantly, feedback from our community of users.
- Peer-Reviewed Research: Our algorithms are derived from data published in high-impact medical and scientific journals.
- Statistical Modelling: We use proven mathematical methods to synthesize data from multiple studies into a single, cohesive estimate.
Our Statistical Model
Estimating pregnancy probability is a complex task. We do not use simple averages. Instead, our proprietary algorithm creates a personalized baseline chance of conception based on your unique inputs (age, health factors, etc.). This baseline is then adjusted using a statistical model that creates a probability distribution curve for your menstrual cycle, allowing us to estimate your fertility for each specific day.
The Key Factors in Our Algorithm
Estimating the probability of conception is a complex task. Our proprietary algorithm integrates multiple key variables to provide a personalized estimate.
Female Age
A primary driver of fertility. Our model accounts for the natural decline in egg quantity and quality over time, based on guidelines from the American College of Obstetricians and Gynecologists (ACOG).
Male Age
Male fertility also declines with age, affecting sperm health. Our algorithm considers this factor, especially for partners over 40, as supported by research on paternal age.
Intercourse Timing
We analyze the timing of intercourse relative to the fertile window, incorporating data showing that intercourse frequency can be more effective than targeted ovulation timing alone.
Body Mass Index (BMI)
A healthy BMI is crucial for hormonal balance. Our calculations are adjusted based on studies linking BMI to fertility outcomes.
Lifestyle Factors
Our advanced models incorporate data on how choices like smoking or alcohol consumption can impact hormonal regulation and overall fertility.
Contraceptive Use
We use large-scale study data, including the landmark Trussell (2011) study on contraceptive failure, to factor in typical and perfect-use rates.
Data Sources & Primary Research
Our algorithm is built upon a foundation of key peer-reviewed studies. The primary sources for our initial models include:
- Contraceptive Failure Rates:
- Trussell, J. (2011). “Contraceptive failure in the United States.” Contraception, 83(5), 397–404.
- Kost, K., et al. (2008). “Estimates of contraceptive failure from the 2002 National Survey of Family Growth.” Contraception, 77(1), 10–21.
- Sexual Frequency & Age-Related Fertility:
- Twenge, J. M., et al. (2017). “Declines in Sexual Frequency among American Adults, 1989-2014.” Archives of Sexual Behavior, 46(8), 2389–2401.
- Hendershot, G. E., et al. (1982). “Infertility and age: an unresolved issue.” Family Planning Perspectives, 14(5), 287–289.
For a complete list of the dozens of studies and data sets used in our models, please visit our full Research Library.
Continuous Improvement: How We Evolve
A great tool is never truly finished. We are dedicated to ongoing innovation based on new research and user feedback.
“Since our launch, we’ve been privileged to gain the trust of hundreds of thousands of users worldwide. This extensive user base has provided invaluable feedback, enabling us to refine and enhance our products continually.”
This feedback loop has led to significant enhancements, including algorithm refinements, user experience improvements, and the addition of new features in response to popular demand.
Important Note & Medical Disclaimer
The Pregnancy Chance Calculator provides estimates based on statistical models and is intended for informational purposes only. It is not a substitute for professional medical advice. For personalized medical guidance, diagnosis, or treatment, please consult a qualified healthcare provider.