Basal Body Temperature (BBT) Ovulation Tracker

Basal Body Temperature (BBT) Ovulation Tracker is evaluated from Pre-Ovulation Average Temp, Post-Ovulation Average Temp and Last Menstrual Period. The calculation reports Temperature Rise, Thermal Shift Detected and Estimated Ovulation Date.

Results

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About the Basal Body Temperature (BBT) Ovulation Tracker

Basal Body Temperature (BBT) Ovulation Tracker is treated here as a quantitative relation between Pre-Ovulation Average Temp, Post-Ovulation Average Temp, Last Menstrual Period and Day of Cycle When Shift Detected and Temperature Rise, Thermal Shift Detected, Estimated Ovulation Date and Estimated Luteal Phase Length.

The calculator uses a multi formula configuration. Each reported value is read as a direct evaluation of the stored rules with the declared field formats and units.

Formula basis:
Temperature Rise = Post-Ovulation Average - Pre-Ovulation Average
Shift Confirmed: >= 0.2 degF sustained rise over 3+ days

Interpret the outputs in the order shown by the result fields. Optional inputs affect only the outputs that depend on those variables.

Formula & How It Works

The calculation applies the following relations exactly as recorded in the metadata:

Temperature Rise = Post-Ovulation Average - Pre-Ovulation Average
Shift Confirmed: >= 0.2 degF sustained rise over 3+ days

Each output field is produced by substituting the supplied inputs into the relevant relation and then applying the declared rounding or text format.

Worked Examples

Example 1: Clear Thermal Shift — 0.4°F Rise

Inputs

pre_ov_avg: 97.3 post_ov_avg: 97.7 lmp_date: 2024-01-01 days_until_shift: 14
Temperature Rise: 0.4 degF. Thermal Shift Detected: Yes - Thermal Shift Confirmed (>= 0.2F rise). Estimated Ovulation Date: 2024-01-0113 days. Estimated Luteal Phase Length: 14 days

With Pre-Ovulation Average Temp = 97.3, Post-Ovulation Average Temp = 97.7, Last Menstrual Period = 2024-01-01 and Day of Cycle When Shift Detected = 14 as the stated inputs, the result is Temperature Rise = 0.4 degF, Thermal Shift Detected = Yes - Thermal Shift Confirmed (>= 0.2F rise) and Estimated Ovulation Date = 2024-01-0113 days. Each value corresponds to the declared output fields.

Example 2: Borderline Shift — 0.15°F Rise

Inputs

pre_ov_avg: 97.5 post_ov_avg: 97.65 days_until_shift: 16
Temperature Rise: 0.15 degF. Thermal Shift Detected: Possible - Borderline Shift (0.1-0.19F rise). Estimated Ovulation Date: 2026-05-0715 days. Estimated Luteal Phase Length: 12 days

With Pre-Ovulation Average Temp = 97.5, Post-Ovulation Average Temp = 97.65 and Day of Cycle When Shift Detected = 16 as the stated inputs, the result is Temperature Rise = 0.15 degF, Thermal Shift Detected = Possible - Borderline Shift (0.1-0.19F rise) and Estimated Ovulation Date = 2026-05-0715 days. Each value corresponds to the declared output fields.

Example 3: Monophasic Pattern — No Ovulation

Inputs

pre_ov_avg: 97.4 post_ov_avg: 97.45
Temperature Rise: 0.05 degF. Thermal Shift Detected: No Confirmed Shift Detected (< 0.1F rise). Estimated Ovulation Date: 2026-05-0713 days. Estimated Luteal Phase Length: 14 days

With Pre-Ovulation Average Temp = 97.4 and Post-Ovulation Average Temp = 97.45 as the stated inputs, the result is Temperature Rise = 0.05 degF, Thermal Shift Detected = No Confirmed Shift Detected (< 0.1F rise) and Estimated Ovulation Date = 2026-05-0713 days. Each value corresponds to the declared output fields.

Example 4: Pregnancy Suspected — Elevated Luteal Phase

Inputs

pre_ov_avg: 97.2 post_ov_avg: 98.1 lmp_date: 2024-02-01 days_until_shift: 13
Temperature Rise: 0.9 degF. Thermal Shift Detected: Yes - Thermal Shift Confirmed (>= 0.2F rise). Estimated Ovulation Date: 2024-02-0112 days. Estimated Luteal Phase Length: 15 days

With Pre-Ovulation Average Temp = 97.2, Post-Ovulation Average Temp = 98.1, Last Menstrual Period = 2024-02-01 and Day of Cycle When Shift Detected = 13 as the stated inputs, the result is Temperature Rise = 0.9 degF, Thermal Shift Detected = Yes - Thermal Shift Confirmed (>= 0.2F rise) and Estimated Ovulation Date = 2024-02-0112 days. Each value corresponds to the declared output fields.

Common Use Cases

  • Analyze BBT readings to detect ovulation
  • Determine if ovulation has occurred from temperature data
  • Combine BBT with cycle length for fertility planning
  • Identify BBT thermal shift pattern