Trying to understand your odds? Get a quick, baseline estimate in seconds. For a more personalized result, try our Advanced Calculator below.
Ready for a Deeper Analysis?
The simple calculator provides a baseline. For our most accurate estimate, the Advanced tool includes your unique profile—factoring in age, BMI, and lifestyle.
Try the Advanced Calculator Our Most Popular ToolTry Our Advanced Pregnancy Chance Calculator
Standard estimates don’t tell the whole story. For our most nuanced calculation, use the Advanced tool below. It considers your unique profile—including age, BMI, and lifestyle—to generate a more precise result.
How to Use Our Calculator
Simply enter the optional information and press the “Calculate” button. The more information you enter, the more accurate the pregnancy estimation will be. Don’t worry, we don’t store your data.
This calculator is designed to estimate pregnancy odds over a real or hypothetical period of time.
Contraceptive Method (optional): Select a contraceptive method (or 2 in the advanced calculator).
Intercourse Times: During the period of time, how many times did you have intercourse? (e.g. 50)
Female Age: During the period of time, what was the age of the female participant? (e.g. 37)
How Our Calculators Work: The Science Behind Your Estimate
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
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.
Medical Disclaimer
The Pregnancy Chance Calculator is based on peer-reviewed scientific research to provide accurate estimates of pregnancy chances. However, it is not a substitute for professional medical advice, diagnosis, or treatment. Always consult with a healthcare provider for any medical concerns or questions about your fertility.