Tempdrop vs. Oral thermometer – Are they the same?

What's the difference between oral BBT thermomerters & Tempdrop?

The temperatures from your Tempdrop will not be the same as the temperatures from your oral thermometer each day… and that’s ok! They don’t need to be the same because they obtain your temperature in a different way.
The most important thing for accurate results is that you stay consistent with your thermometer throughout your cycle!

For 12% off Tempdrop use code BRIGHTGIRLTD

Let's compare Tempdrop with oral thermometers!

The difference between Tempdrop and an oral thermometer is where they take your temperate from; the Tempdrop takes your temperature from your axillary artery under your arm while you sleep, and an oral thermometer gets your temperature when you wake up from the heat pockets under the tounge.


  • Takes temperature from axillary artery under arm 

  • Worn throughout the night

  • >$150

  • Temperature will be accurate no matter what time you wake up
  • Can be used by people with irregular sleep schedules (new parents, insomnia, shift workers)

Oral thermometer

  • Takes temperature from under tongue in ‘heat pockets’ of the mouth

  • Taken first thing upon waking after 3-4 hours of uninterrupted sleep

  • ~$15-$30

  • Temperature needs to be taken at the same time each day

  • Can’t be used by people with irregular sleep schedules (new parents, insomnia, shift workers)

Tempdrop & Oral temperatures won't match

Temperatures from Tempdrop and an oral BBT thermometer won’t match or be exactly the same each day. This is expected because they take readings from a different place on your body. Don’t stress! This isn’t just ok… it’s expected!

If you were to track with both Tempdrop and an oral thermometer, you’d expect to see temperatures that form the same overall pattern on your chart. This doesn’t mean they need to match each day.

When charting your BBT for fertility you’re looking for an overall shift in basal body temperature through a temperature rise.
Rather than focusing on each day’s specific reading, you’re watching for the shift from lower temperatures to higher temperatures after ovulation. 

Tempdrop, have published on their website that:
“Tempdrop can read in a different range (higher or lower) than BBT, and the first 14 days may be more up and down as the Tempdrop sensor algorithm filtering has not yet started.”

The image above shows how Tempdrop and oral temps can differ each day, but both still follow the same overall pattern. In this chart, both the Tempdrop and oral temps show a temperature shift to confirm ovulation, although with a 1 day difference. When using the sympto-thermal double-check method, you can double check the closing of your fertile window with cervical mucus sign to ensure your fertile window is over.


Learn Fertility Awareness with me!

Hi, I’m Demi!
I’m a certified double-check sympto-thermal method teacher. 
In other words… I teach the method that has 98%-99.6% effectiveness!

I’ve been using FAM as birth control for over 5 years now. It’s saved me a lot of money and contraception side-effects!

I’d love to work with you to either conceive quicker, or ditch hormonal birth control! 

Switching from oral to Tempdrop: The most important thing

If you’re switching from an oral BBT thermometer to Tempdrop, or vice-versa, the most important thing is to stay consistent with what you use throughout your whole cycle.

The best time to switch is at the start of a new cycle. 
If you’ve purchased a new thermometer, try to finish your current cycle using your old thermometer before starting with a new one. Switching thermometers mid-cycle can interfere with the accuracy of your BBT results.


Pros & cons of Tempdrop


  • Allows people with irregular sleep schedules to track their BBT
  • Syncs with your phone
  • You don’t need to remember to take oral temps every day when waking
  • Their customer service and help/tech support is very good
  • Integrates and syncs with popular period tracking apps like Read Your Body
  • The basic version of the Tempdrop app is free
  • Premium version of the app is available
  • Sleep data is available if you upgrade your Tempdrop app 
  • They are always updating the capabilities of the Tempdrop & app, meaning you get more out of your purchase as time goes on
  • The price is extremely reasonable for what it can do


  • The initial expense 
  • If you don’t wear it properly, it won’t record your temperature
  • The feeling of the armband touching you while sleeping can take a while to get used to for some people

Note: Tempdrop advises that users who are trying to avoid pregnancy should use their Tempdrop for 1 cycle before using their Tempdrop temps within a fertility awareness method. This helps to ensure you’re using your Tempdrop correctly. In this time you can use other fertility signs to determine your fertile window OR use barrier methods (confirm with your FAM trainer what your best pathway would be).

Watch my Tempdrop review video review here:

For 12% off Tempdrop use code BRIGHTGIRLTD

Products in this post:

Tempdrop wearable thermometer (BRIGHTGIRLTD for 12% off)
Fertility2Family oral BBT thermometer (BRIGHTGIRL15 for 15% off)

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