Basal Body Temperature Charting for Beginners
Basal body temperature (BBT) is your temperature at complete rest. After ovulation it rises slightly, by about 0.2 to 0.5 °C, and stays higher until your next period.
How to chart
Take your temperature first thing every morning, before getting up, at about the same time each day, and record it.
Reading the chart
A rise that lasts at least three days shows ovulation happened just before it. If the higher temperature lasts more than about 18 days, it can be a sign of pregnancy.
The catch
BBT confirms ovulation after it has happened, so it's most useful for learning your pattern over several cycles.
Ovulation Calculator: Predict ovulation days for your next three cycles.
Open the calculatorThis article is general information, not medical advice. Talk to a doctor or midwife about your own pregnancy or fertility.