Richie Cotton created a graph tracking a woman's probability of getting pregnant.

Putting his penchant for data analysis to practical use, Richie Cotton, compiled a chart to help himself and his girlfriend understand how long it will take for them to conceive.

Women tend to be less fertile as they get older, but how much, exactly? Math nerd Richie Cotton at 4dpiecharts.com decided to figure it out with a chart.

Cotton, who is trying to have a baby with his girlfriend, used data from the Journal of Human Reproductie Sciences and Social Fertility to figure out "monthly fecundity rate," or likelihood of getting pregnant each month if you're having sex without birth control. A healthy, average woman of 25 has an MFD of 25 percent. MFD decreases to 10 percent for a woman of 35. He then put the data in some formulas to plot out the chart.