Babykk: I don't think there is any range it's up to individual body yeah? Hmm I din use a bbt thermometer. But use normal thermometer with one decimal. Hmm I will poke inside my mouth after my alarm sound every morning before jump out of the bed or drink any water. That all quite easy. And record the temp in my phone when I'm on the way to work. From the temperature record you can go make a chart or use website to generate the chart!