Choosing a Basal Body Thermometer

Not all thermometers are suitable for fertility awareness charting. The temperature changes we're looking for can be small, so choosing a thermometer that measures and displays temperatures with sufficient precision is important.

For symptothermal fertility awareness methods, look for a basal body thermometer that displays temperatures to two decimal places, for example 36.42°C. A typical fever thermometer that displays only one decimal place, such as 36.4°C, doesn't provide the same level of detail needed for charting these small temperature changes. Ear and forehead thermometers are also not suitable for this purpose.

The good news is that you don't need to spend a fortune on a thermometer. There are plenty of options to suit different budgets and preferences, from a simple digital thermometer to models with memory, backlighting or Bluetooth syncing.

Here's what to look for and some options to consider.

1. Basic and budget-friendly thermometers

If you're happy to enter your temperatures manually, a simple digital basal body thermometer can be all you need.

Look at options from:
• Easy@Home: Offers basic digital basal body thermometers, with features varying by model.
• Femometer: Offers digital thermometers designed for temperature tracking, including simpler models.
• Pharmacy or other readily available options: You may find a suitable digital thermometer without needing to buy a feature-rich model. Check the manufacturer's specifications carefully to make sure it is suitable for basal body temperature charting.

You don't need Bluetooth, an app or automatic syncing to chart your temperature. A suitable thermometer that meets the precision and measurement requirements of your chosen method is sufficient.

2. Thermometers with additional features

Some thermometers offer extra features that make taking and recording your temperature more convenient.

Features to look out for include:
• Memory recall: Stores one or more previous readings, depending on the model, so you can check your temperature again if needed.
• Backlit display: Makes the reading easier to see in a dark bedroom.
• Waterproof or easy-clean design: Can make cleaning and care more straightforward, subject to the manufacturer's instructions.

These additional features are conveniences rather than necessities. Choose the features that are useful to you rather than assuming that a more expensive thermometer will produce better charts.

3. Bluetooth basal body thermometers

If you prefer not to enter your temperature manually, some thermometers can transfer readings to a compatible app using Bluetooth.

Options to investigate include:
• Easy@Home Bluetooth models: Check the specifications of the particular model, as Bluetooth connectivity and other features vary.
• Femometer Vinca 2.0: A Bluetooth-enabled basal body thermometer designed to sync readings with the compatible Femometer app.

Automatic syncing can make recording temperatures easier and reduce the need to enter readings manually. However, it isn't essential for fertility awareness charting.

Before purchasing, check that the model displays the temperature precision required by your method and that you can access the actual readings you need.

4. What about smart rings and watches?

Smart rings and watches can be appealing because they measure temperature overnight without requiring you to take a manual reading each morning.

However, their temperature readings can be erratic for fertility awareness charting. Devices may use different sensors, measurement techniques and algorithms, and the temperature data they display may not be suitable for applying the rules of an established fertility awareness method.

I don't generally recommend smart rings or watches for fertility awareness charting. A device measuring temperature overnight isn't automatically suitable for interpreting the temperature changes used in fertility awareness.