DOs and DON’Ts of BBT Charting


The overall goal of BBT charting is to help you understand your body’s ovulatory and cycle patterns. It’s not an exact science so don’t panic if you accidentally oversleep once or occasionally forget to write down your daily temp. That being said, there are some general guidelines of what and what not to do so you achieve success in your charting and ultimately your reproductive goals.


  • Do purchase a thermometer that is sensitive enough to read to the one-hundredth (0.01) of a degree Fahrenheit.

  • Do keep all of the supplies you need (thermometer, Glow app, etc.) on your nightstand or somewhere handy so they’re immediately accessible when you wake up.

  • Do start charting on the first day of your menstrual cycle, a.k.a. Cycle Day 1.

  • Do try your best to take your temperature at around the same time each morning (including on the weekends). Set up a Glow reminder to help you stay on track.

  • Do make sure that you take your temp before doing anything else - before eating, going to the bathroom, or even sitting up in bed.

  • Do be sure to be consistent with whichever method - orally, vaginally, or rectally - that you choose for taking your temperature. Do it the same way each time for the most accurate results.

  • Do remember to record the temperature after you’re done measuring.


  • Don’t use a regular thermometer that you would use for measuring your temperature while sick. Unfortunately, that kind isn’t sensitive enough for what you need.

  • Don’t move around before taking your temperature. Even just lying in bed awake for a few minutes before temping can affect the reading.

  • Don’t rely on memory for recording your temperature later. Record it in the Glow app as soon as you measure for the best accuracy.

  • Don’t go to bed too late. Remember, you need to sleep for at least 5 hours total and 3 consecutive hours of sleep before waking for a reliable temperature reading.

  • Don’t drink alcohol the night before. The reason being that drinking can cause elevated temperatures the next morning. (But hey - we’re all human, and if you decide to have a drink, just make note of it on your Glow log.)

  • Don’t worry too much about any one temperature until you’ve tracked the entire cycle.

Remember, these are simply guidelines to help you achieve success with your tracking. Like we mentioned before, charting BBT isn’t a perfect science and it’s okay if you have an occasional slip-up (don’t feel bad, it happens). Just remember to log it in Glow. And if there is a questionable reading or confusion around your fertile window, you can always check your cervical mucus or cervical position for some extra help, too.

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