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BBT Charting Basics! Everything You Need To Know About BBT & Ovulation Tracking

Learn the basics of bbt charting to get pregnant and track ovulation

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BBT Charting Basics 101!

How taking your Basal Body Temperature (BBT) Daily Can Help You Track Ovulation & Get Pregnant

I’m going to start this post off by saying that BBT charting is the biggest pain in the ass method of tracking….. EVER!

If you have a hard time with OPKs run …..

I mean you can screw up your chart by even turning over too quickly in bed and raising your BBT (basal body temperature) just .01 of a degree.

Now, I am not saying this to discourage you but I do feel like it is important to be real.

BBT Charting was NOT for me but that doesn’t mean it isn’t for you.

I think you should know what you’re getting into because it requires dedication and precision timing and MONTHS of tracking to even get an idea of what your, unique body does temp wise during your cycle.

I did not have the patience for all of that. I am more of a do something TODAY to get pregnant than a wait it out and see type of person.

If I have scared you off completely you might just want to browse the getting pregnant section and see if there is something else that interests you.

If you’re determined to learn the basics of BBT charting then read on…


What is BBT & How it’s different from your Regular Temp?

Your body’s core temperature fluctuates throughout the day for varying reasons – hot shower, emotions, illness, cold weather, etc.

Your basal body temperature (BBT) is your body’s lowest temperature point in a given day (24 hour period).  Which is calculated upon waking.

Basically, it’s your body’s resting core temp.

It’s similar in concept to calculating your resting heart rate, the main difference is that you’re not taking an average based upon different measurements throughout the day.

When taking your BBT you are pretty much taking a magnifying glass to your temperature. “Regular” thermometers that we are all used to only show up to a 10th of a degree.

To get your BBT you need a specific type of thermometer called a Basal Thermometer. A BBT thermometer has a higher accuracy rate at a 100th of a degree.

If you’re thinking “Okay, cool – this doesn’t sound to bad just grab a new thermometer, she was just being dramatic!”

Get ready to buckle up because no we are going to dive into the real “basics of BBT charting” and it ain’t pretty.

What is a BBT chart and how do you use it?

A BBT Chart is a graph that you used to plot out your basal body temperature every day. It takes three to four months of tracking to really understand your chart.

You’re looking for a SLIGHT increase in your BBT around the same point in time within each of your cycles.

When you’re able to identify this increase that means you have ovulated and are in the LP (Luteal Phase). The increase is DPO 1 (days past ovulation)

You can print out a BBT chart for the good ol’ pen and paper approach, or you can use an app.

Types of BBT Charts

Fertility Tracking App with A BBT Chart Built in

If you’re using a fertility tracking app most likely you’ve noticed an area or tab that is dedicated to BBT charting.

All you have to do is input your daily temp and the app will create a visual chart for you.

It’s easy, and you’re unlikely to lose your data. It also helps the app predict ovulation for you, depending on how your app works.

You can also buy a Basal Thermometer that has Bluetooth built-in. The thermometer automatically syncs to an app – you don’t have to input anything! Ah, technology is crazy!

Method 2: Pen & Paper

If you prefer to have a physical, hard copy of your BBT chart you can easily find one online and download one.

You will need to mark your own dots and connect them to see the dips & spikes.

I was going to make a printable BBT Chart for you guys and then decided against it. I feel like the majority of you guys will go the app route so no need to waste time designing one.

How to Measure your BBT

Alright, so now that we have covered the different types of BBT charts and that you need a special Basal thermometer it’s time to discuss how to actually measure your BBT to figure out ovulation.

This is where things start to get dicey!

This “course” is about to go from Basic BBT Charting 101 to Advanced BBT Charting for Biochemists.

And here we Goooooo…..

How to Take Your BBT with your New Thermometer

  • Step 1: Put the thermometer in your mouth, wait for the beep, and record the data.

And now…..

How to take your BBT without Forking it up


  • Before you even open your eyes feel around slowly for your BBT thermometer and lazily plop it in your mouth. The second you wake up, you need to have that thermometer in your mouth. Make sure you place it somewhere you can easily grab it without using any energy because…
  • YOU CAN NOT MOVE!!! You cannot stretch, talk, sit up, get a drink, go pee NOTHING before taking your temp. Or you will not get an accurate reading.
  • You need four hours of solid sleep, without waking AT ALL to get an accurate BBT in the morning. If you get up to pee, get a drink of water or take the dog out in that four-hour window before it’s time to get up.. you’re screwed your results will be jacked.
  • You need to place the thermometer in the same part of your mouth every morning and keep the same depth. BTW you can also take your temp vaginally and rectally, but I am just going to assume most of you will go the oral route.
  • Misplace your thermometer and you have to start all over. Even if you replace it with the same brand.

As you can see there are A LOT of ways you can screw up your results.

Don’t forget that it also take a solid 3 months, sometimes more of BBT Charting to get an idea of when you’re ovulating.

But, if you’re disciplined and feel like you can manage to follow all the “rules” BBT Charting can help you learn your body and predict ovulation.

How long after ovulation does it take for your BBT to rise?

After you ovulate your BBT rises the very next day.

Before you ovulate your basal body temp will most likely range from 97.00 to 97.70 Fahrenheit.

The day AFTER ovulation has occurred you will notice a slight spike in your BBT by 0.5 to 1.0 degree.

This spike lasts until your next period or until you get a positive pregnancy test.

How to Read Your BBT Chart Results to Detect Ovulation

When you’re BBT charting you are looking for a pattern (part of the reason you need 3+ months of cycle data).

Your temp is going to fluctuate throughout your entire cycle but you will start to notice that before ovulation your BBT is lower and then right after you’ll see a temp spike.

Some women have a noticeable dip in BBT the day of ovulation, followed by the temp spike the day after. If you happen to be one of these women you may not have to wait as long to get an accurate reading from your BBT chart.

You are looking for three or more consecutive days at a higher BBT. Once you see that your temp has risen you can go back to your chart and look for the cycle day before the rise in temp.

How to tell if Your BBT Chart will lead to a BFP

image taken from the Fertility Friend app

Alright, so you charted your temp and you think you you have nailed down ovulation day – so now what?

Now, you wait. You should keep on taking your BBT every day and keep your FX (fingers crossed) that your BBT chart BFP is on the way.

Some women may notice what is called an implantation dip in their BBT chart, which is a very good indication that a BFP is just around the corner.

You should start looking for an implantation dip around day 6-11. Your temp will only drop for one day and then shoot back up.

The other thing to look out for that may indicate pregnancy on your chart is something called a triphasic pattern. Which is fancy for three noticeable elevations in your BBT from the point of ovulation.

Basically, if you are seeing a steady upward trend in your temp then the odds of you getting a BFP are very high.

And of course if you hit CD (cycle day) 15+ with no sign of AF (aunt flo) then go POAS (pee on a stick) and keep your FX for that BFP!

Honestly, the TWW (two-week wait) tends to be the time of most “craziness” for TTCers.

Every little symptom has you questioning if you’re pregnant (well, at least I know it did for me). But, remember your BBT can fluctuate and can be rendered inaccurate just from getting up to pee too close to temp taking time.

In my opinion, it’s best not to count on it to indicate pregnancy – and I know that 90% of you that are going to try temp tracking will ignore that advice.

Because it’s so dang hard to not look for those early pregnancy signs!


BBT Charting Basics FAQ

How accurate is BBT Charting?

Some studies suggest that BBT charting is only 22% accurate.1Steward K, Raja A. Physiology, Ovulation And Basal Body Temperature. [Updated 2020 Jul 27]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from:

Does Clomid affect BBT accuracy?

It can, yes. Sometimes it will cause an increase in your BBT and it can also delay the Luteal phase. I really wouldn’t bother with it if you are taking Clomid, or any medication regularly for that matter.

What if I don’t notice a temperature spike? Does that mean I am not ovulating?

Due to the nature and sensitivity of BBT charting I really wouldn’t read too much into it if you do not notice a temperature spike. As mentioned above any little thing can jack up your readings.

How do OPKs (ovulation predicator kits) and BBT Charting work together?

OPKs detect a surge in LH (luteinizing hormone) indicating that ovulation is 12-48 hours away. So by combining OPKs with BBT charting you essential having something that tells you when are getting ready to ovulate, when you ovulated and when to start counting DPO (days past ovulation).

How long will be temperature stay elevated if I am NOT pregnant?

The spike in temperature occurs during your LP (luteal phase), if you are not pregnant you should start to see a dip around day 14-15. If you notice that your BBT starts to decline significantly before CD14 then you may have a LP defect and it would be a good idea to contact your doctor.

How many cycles do I have to chart for before I can estimate ovulation?

It is best to chart for at least three months before you start to rely on BBT Charting to detect ovulation. This way if you have any outside factors that disrupt your temping schedule you already have a general idea of when you will ovulate.

Should I have sex if I see a temperature drop around suspected ovulation time?

Yes, absolutely. Ideally, you will want to have sex more than just on the day of the temperature drop. It’s a good idea to have a plan in place, like a Baby Making Blueprint to help you get pregnant.

Now the real Question: Should You Start BBT Charting?

It defiantly wasn’t for me, as you can see after reading this whole post, the “Basics” of BBT Charting aren’t so basic after all.

More like a high-maintenance, extra friend that you love, but can only take so much off at a time.

It takes time, patience, and some serious dedication to chart your BBT. 

If you’re just starting out TTC I highly recommend trying OPKs (ovulation predictor kits) for a few months before resorting to charting. The hardest part of using OPKs is trying to figure out when to take them – which is minimal stress compared to BBT charting.

Trying to temp, read, and track using a BBT chart can become overwhelming and cause unneeded stress.

If you find that it is too much for you then discontinue charting and just stick with OPKs.

Will You Be BBT Charting? What Are You Currently Doing To Track Ovulation?

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