A BBT chart is used to track fluctuations in basal body temperature (BBT), which is your body's temperature at rest. Because a slight rise in temperature occurs at the time of ovulation, tracking BBT over time helps identify low and peak fertility. (Check out our intro to BBT charting.)
Digital tracking with the use of various apps has become a popular way to track BBT, but for some, the traditional paper and pen method of tracking is the way to go.
If you have determined that pen-to-paper is your method, finding a paper chart with the ideal layout for you is next. Here is a selection of BBT charts that might do the trick.
Free Printable Ovulation Chart Options
Source: Taking Charge of Your Fertility
Download BBT Charts
Fertility In Focus available on Etsy $3.00