When looking for a thermometer to use for cycle charting, you want to look for a basal body thermometer. You shouldn’t compromise on this. Basal body thermometers, or BBTs for short, read to the 100ths (98.68) rather than 10ths (98.6). This provides the highest accuracy. To learn more about how to get the most out of your basal body temperatures, read my Basal Body Temperature Troubleshooting Guide.
My recommendations below are based on my personal experience as well as my experience as a Fertility Awareness Educator. For over 3 years now I have been teaching women how to chart their cycles. I’ve gotten to see how brands and models perform over time. I also have a trained eye to evaluate product reviews to know when bad reviews are not due to the actual product. So you can be confident that you’ll get a good thermometer if you choose one from this list.
Features to consider:
- Back light – ideal if you’re taking your temperature in the early morning before the sun comes up
- Measurement time – most methods recommend a minimum of 3 minutes, the longer the thermometer stays in your mouth, the more accurate the temperature will be. If you choose a thermometer with a shorter temp time and find that you have unstable temperatures, consider leaving the thermometer in your mouth for 2 minutes before turning it on.
- Memory – Some people find they get more stable temperatures by waking early in the morning (5-6am) to take their temperature and then going back to sleep until their normal wake time. Having a thermometer with a memory allows you to fall back to sleep immediately and enter your temperature when you finally wake for the day.
- Alarm – Taking your temperature at the same time every day is important for accuracy and consistency. If you try to keep your phone away from your bed, then a thermometer with a built in alarm could be ideal.
Thermometers to consider
This thermometer has been around for several years and is fairly popular. It is one of the most affordable, basic BBTs. If you’re on a tight budget this is a good option. If you have some wiggle room in your budget I would recommend choosing one of the other options.
I personally used this thermometer for several months and while it’s a usable thermometer I found I preferred another brand. It appears to have been updated in 2022 so maybe it has improved. It appears to still be a decent option.
- It’s affordable (around $9) and can often be found on sale
- Has last temperature taken memory recall
- Can be switched to celsius
- 1 minute temp time (on the shorter side of ideal)
- No backlight
Easy@Home tends to be a very dependable brand. This budget model is one of the most commonly used options. It’s still very affordable while offering sought after features.
- It’s affordable (around $15)
- It has a backlight
- 90 second temp time (could stand to be longer but is more ideal than quick read)
- 30 temperature memory
- C/F switchable
- Backlight is blue (many people prefer the orange backlights so the blue light doesn’t interfere with sleep)
- 90 second temp time is still on the shorter side of ideal
This Easy@Home model is an upgrade from the EBT-100. It is a bluetooth thermometer and can sync with the Premom app but I really don’t recommend using it as your primary charting app. The bluetooth option is really nice to have for the purposes of backing up your temperatures. The extra info on the display is a nice addition that most thermometers don’t offer. It’s also available in purple.
- Orange back light
- 30 temp memory in the thermometer itself
- Unlimited memory when synced with the app
- Time and date on the thermometer display
- 90-120 seconds read time
- C/F switchable
- Encourages use of the Premom app, which is not ideal for accurate charting
- Runs about $40 but can be found on sale
- ??? Honestly I couldn’t find a lot of cons, this seems to be a great thermometer and it’s popular
This is my personal favorite, you can read my full review here. This thermometer connects by bluetooth to the Femometer app where you can customize the thermometer settings and sync your temps to the Femometer chart (not an app I recommend for charting). It has the temperature readout directly on the thermometer (whereas Vinca 1.0 does not) so after you customize your settings you don’t really need to use the app.
- C/F switchable
- Back light
- 1-3 minute temp time (Mercury setting for 3 minutes)
- Memory in the app with date and time
- Customizable alarm
- Customizable volume
- Battery level display in app
- May be out of budget for some ($40-60 can sometimes be gotten on sale)
- Defaults to shorter temp time
A wearable thermometer that goes on your upper arm near your armpit or in your sleep bra all night. It has a proprietary algorithm that may help some people get more stable temperatures. People with irregular sleep schedules tend to like this thermometer but in my experience it can be quite inaccurate for those who are postpartum or have PCOS.
- Helps many people chart who feel they wouldn’t be able to with a standard BBT
- 99% of users surveyed said they were happy with their experience
- Temps all night long
- A large Facebook community
- May be uncomfortable for some people when worn on the arm (especially for larger arms)
- Some people may experience delayed temperature shifts compared to oral temps (I am seeing this more frequently since the 2023 algorithm update)
- Can give false temperature shifts to some users
- Customer service tends to leave a lot to be desired
Tempdrop has a cult following but after using it for 3 years, working with many clients who have used it, and observing support group posts on Facebook, I only recommend using Tempdrop as a last resort. There are methods of cycle charting that do not require temperatures. If you find taking your temperature difficult and troubleshooting has not helped, I would recommend learning one of the temperature-free methods before buying a Tempdrop. You can read my full review of Tempdrop here.
Other things of note
I don’t recommend other devices such as Ava, Daysy, OvuSense, or any similar device. These use algorithms that involve rhythm method type calculations that may not be accurate. A lot of unintended pregnancies have occurred for women trying to avoid, and a lot of missed opportunities for women trying to conceive. My best recommendation is to learn how to interpret fertility signs and symptoms yourself.