1) First 5 Days Rule: You are safe the first 5 days of your menstrual cycle if you had an obvious temp shift 12-16 days before.
2) Dry Day Rule: You are safe to DTD after 6PM if you have been dry all day.
Post ovulation rules:
1) Peak Day Rule: The last day of fertile mucus is called the peak day (the day before your mucus begins to dry up). You are safe to DTD on the fourth consecutive day after the peak day. If another patch of more fertile mucus appears, start your count over.
2) Temperature Shift Rule: You are safe the evening of the third consecutive day your temp is above your coverline. If your temp falls at or below the coverline during the 3 day count, begin your count again.
BOTH rules must be satisfied to be considered in your infertile phase.
How to set a coverline:
When you see a temperature shift of at least 0.2° F above the highest of the previous 6 temps, draw a line 0.1° F above that highest temp.
Related Wiki Resources:
Reasons to Choose Natural Family Planning - Why would you want to use charting to plan your family, anyway? Feel free to add your own reasons for charting!
Types of Natural Family Planning - It's not just the rhythm method. They've got this down to a science with options galore!
NFP or FAM Methods While Breastfeeding - You have options in the postpartum period while your fertility is returning!
Resources For Learning About Fertility Cycles - Find books to read or websites to visit, find an instructor, post your chart online, and learn about how your diet affects your fertility.
Common Abbreviations for Charting to Avoid/Fertility Awareness - BBT, EWCM, TCOYF, and more! Learn what all these crazy acronyms mean here.