BBT Ovulation Calculator

Take your temperature at the same time every morning before getting out of bed, using a basal thermometer (accurate to 0.1°F). After ovulation, your temperature rises 0.2-0.5°F and stays elevated. The rise confirms ovulation has already occurred.

The BBT rise typically occurs 1-2 days after ovulation. Since it confirms ovulation after the fact, BBT alone is better for confirming your cycle patterns over months than for timing intercourse in the current cycle.

Pre-ovulation (follicular phase): 96.0-97.5°F (35.5-36.4°C). Post-ovulation (luteal phase): 97.0-98.5°F (36.1-36.9°C). The absolute numbers matter less than seeing a consistent shift of 0.2°F+ between phases.