4 Best BBT Thermometers to Track Fertility & More 2026

Tracking your cycle can dramatically increase your chances of successfully conceiving. In fact, a National Library of Medicine study shows that those who use cycle-tracking systems are more likely to conceive within two menstrual cycles than those who don't.

The various phases of the menstrual cycle affect a variety of things used to track the ideal time to try and get pregnant, such as your basal body temperature (BBT) and cervical mucus. Using your BBT, you can look out for a lower temperature pre-ovulation during the fertile window, and a higher temperature during the luteal phase after ovulation.

So, let's find out the best way to measure BBT.

Our Top Picks for the Best BBT Thermometers to Track Fertility & More

We've put together a list of the best BBT thermometers for you and even qualified them for different purposes to meet your specific fertility needs.

So let's dive right in and review each one!

Tempdrop is the best wearable BBT thermometer since it uses an algorithm to monitor your sleep patterns, identify your true resting temperature (BBT), and track your nightly and monthly temperatures. This helps identify your fertility window and ovulation for each cycle.

• Cycle tracking: Sync your Tempdrop readings with the app to track your symptoms so you can verify your ovulation and cycle phases.
• Effective for irregular cycles: Tempdrop is tailored to your sleep patterns and menstrual cycle, so you can still track irregular cycles/patterns.
• Fertility cycle report/statistics: Combining temperature readings with other fertility symptoms can help identify your optimal fertility window.
• Pregnancy tracking: To determine a more accurate due date, you can add nine months to your temperature shift date, then subtract 7 days.
• Price: $215

Whether you have a regular daily routine, work in shifts, are experiencing postpartum, or sleep irregularly, Tempdrop's algorithm learns from you and interprets your data on an individual basis.

Unlike a lot of other smart devices and apps that help you track your fertility, the effectiveness is determined by the fertility awareness method you use. Plenty of users have found it useful as they change intentions through trying to conceive, postpartum charting, and even charting for health. Plus, you can choose to sync your data with the Tempdrop app or any other fertility charting app of your choice.

Apple Watch (newer models, including the Ultra) introduced overnight wrist temperature tracking with the Series 8 (and newer models, including the Ultra). When paired with cycle tracking apps, it uses your wrist temperature trends to retrospectively estimate when you ovulated.

• Retrospective ovulation tracking: It uses your overnight temperature data to confirm when ovulation likely occurred, rather than predicting your fertile window in advance.
• Health app integration: It automatically syncs to Apple Health while you sleep, giving you a daily graph of your temperature shifts compared to your baseline.
• Third-party compatibility: If you want more advanced fertility insights, the Apple Watch can be paired directly with third-party apps like Natural Cycles.
• Price: From $399

When you rely on a smartwatch for cycle tracking, you are measuring skin temperature at the furthest extremity of your body (the wrist), which is easily skewed by environmental factors like a cold room. A recent clinical study confirms Tempdrop's ability to detect ovulation with over 98% accuracy. Compared to standard wrist-based wearables that generally achieve around 93% accuracy, moving the sensor closer to the core with an axillary (underarm) placement represents an 80% reduction in error, making it much more reliable for strict fertility tracking.

» Check out these 10 ways to improve your chances of pregnancy.

Ava is a device worn on the wrist, also only during sleep.

• Cycle tracking: You can view real-time insight into your cycle phases for up to 12 previously recorded cycles.
• Effective for irregular cycles: Ava is not effective for irregular periods as it is recommended for women with a cycle length ranging from 24-35 days.
• Fertility cycle report/statistics: Using the data it collects, Ava pinpoints the 5-day window that's best for you to try for a baby.
• Pregnancy tracking: It offers pregnancy tracking, and if you purchase the Plus plan, you get a full refund if you are not pregnant within 12 months.
• Price: From $279-$359

It captures and tracks physiological signals, your input in the app, and your past cycles to help you interpret and predict your ovulation period and fertility window.

Ava is primarily ideal for women trying to conceive as it offers health parameters that can indicate when is the best time to try and get pregnant. These include temperature, physiological stress, sleep, and resting pulse rate.

Because of the cycle length parameters, many women with conditions like PCOS won't be able to use Ava to help them get pregnant.

• Cycle tracking: Daysy uses a colored-light system to indicate when you are fertile, infertile, and ovulating.
• Effective for irregular cycles: It is designed with some irregularity in mind. But if your cycle is outside the 19-40 day range, you can contact Daysy's experts.
• Fertility cycle report/statistics: Using a unique algorithm, Daysy can calculate the fertile days in your cycle quickly. If the device shows a red light, you are currently or possibly fertile.
• Pregnancy tracking: When your BBT remains high for more than 18 days, Daysy registers a possible successful conception. Then, all three lights will flash, and once Daysy has calculated a more likely pregnancy, all lights will be solid. DaysyDay will then turn your temperature chart blue in the app.
• Price: $319

Daysy accommodates your sleep schedule, only requiring at least 1 hour before using the device. Its self-learning algorithm is based on 5 million menstrual cycles. It uses this insight along with your menstruation and ovulation data and your past cycles to deduce your peak fertility periods.

Daysy's app, DaysyDay, allows you to easily view your temperature curve, so you can make informed choices regarding your fertility, ovulation, and menstrual health. Plus, it offers individualized statistics about cycle irregularities or impacts from your current activities.

» See how charting multiple fertility awareness indicators can help you conceive.

Monitor Your BBT and Fertility With Tempdrop

Traditionally, you have to take your BBT when you wake up at the exact same time, which either means you never sleep in or that your sleep is disrupted so you can take your temperature on time. But with modern BBT thermometers and fertility trackers, this is a thing of the past.

And look no further than Tempdrop. Overall, Tempdrop gives you the freedom to use your cycle data for whatever your intentions are and can make your fertility journey easy to follow and navigate.