BBT Ovulation Chart
Unlock the secrets of your cycle. By tracking your Basal Body Temperature (BBT) every morning, you can pinpoint exactly when you ovulate and identify your most fertile days.
Temp Shift
Detect ovulation
Visual Graph
See the pattern
Cycle Day
Track timeline
Conception
Maximize chances
What is Basal Body Temperature?
BBT is your body's lowest resting temperature, attained during sleep. It subtly changes throughout your menstrual cycle in response to hormones.
The Progesterone Spike
Before ovulation, your temperature is lower (Follicular Phase). Immediately after the egg is released, your body produces Progesterone to prepare the womb. This hormone causes your resting temperature to rise by about 0.5°F to 1.0°F (0.3°C to 0.6°C) and stay high until your next period.
Confirm Ovulation
Standard calendars *predict* ovulation. BBT charting *confirms* it actually happened.
The Shift
A sustained temperature rise for 3 days confirms ovulation occurred the day *before* the rise started.
Early Pregnancy Sign
If your temperature stays high for 18+ days after ovulation, it is a very strong sign of pregnancy.
Easy Logging
Input your daily temperature readings directly. We handle the plotting for you.
Dynamic Chart
Watch your personal fertility curve build day by day. Spot the shift instantly.
Downloadable
Save your chart image to show your doctor or fertility specialist.
Why Chart with Us?
No App Needed
Most BBT apps require sign-ups and sell data. We offer a private, browser-based charting tool.
Dual Units
Works seamlessly with Fahrenheit (°F) or Celsius (°C) thermometers.
Clear Visualization
We highlight the "coverline" zone visually so you can easily identify the temperature jump.
How to Track Successfully
Consistency is the secret to BBT charting.
Buy a BBT Thermometer
You need a special "Basal" thermometer that measures to two decimal places (e.g., 97.56°F). A regular fever thermometer isn't precise enough to catch the tiny shift.
Measure immediately upon waking
Take your temp before you sit up, speak, drink water, or get out of bed. Do it at the same time every morning.
Log the Data
Enter your daily reading into the tool below. Over the course of the month, you will see a distinct pattern emerge showing your follicular (low) and luteal (high) phases.
Your BBT Chart
Enter your temperature readings for this cycle.
Enter your temperature for each cycle day:
How to Read Your Chart
Look for the patterns, not just individual numbers.
Biphasic Pattern
A normal ovulatory cycle has two phases: low temps before ovulation (Follicular) and higher temps after (Luteal). Your chart should look like a staircase that goes up once and stays up.
The Thermal Shift
Look for a temperature rise of at least 0.5°F (0.3°C) higher than the previous 6 days. This jump marks that ovulation occurred the day *before* the rise.
Clinical Insights
What your chart tells your doctor.
Anovulation
If your chart is "rocky" with no sustained rise, you likely did not ovulate. This is common in PCOS.
Pregnancy
If temps stay high for 18 days or more past ovulation, congratulations! You are likely pregnant.
Luteal Phase Defect
If your temp drops less than 10 days after ovulation, your luteal phase may be too short to sustain a pregnancy.
Applications of BBT
Conception
BBT confirms you are actually releasing an egg. It is the most affordable way to verify fertility issues before seeking expensive specialist help.
Natural Birth Control
When used correctly as part of the "Fertility Awareness Method" (FAM), BBT can help couples avoid pregnancy by identifying safe days after ovulation has been confirmed.
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Frequently Asked Questions
Can I use a regular thermometer?
No. You need a basal thermometer that measures to 1/100th of a degree (e.g., 97.56). Regular ones round too much to see the subtle shift.
What if I wake up at different times?
For accuracy, you must measure within the same 30-minute window daily. If you wake up late, your temp will be falsely high.
Does alcohol affect BBT?
Yes. Alcohol can cause a temperature spike the next morning, which can confuse your chart interpretation.
Does BBT predict ovulation in advance?
No. BBT only tells you *after* you have ovulated. To predict it in advance, use Ovulation Predictor Kits (OPKs) or track cervical mucus.