Basal Thermometer

Here you will find the most popular analogue and digital Basal Thermometers, which are suitable for the Symptothermal Method application.

Digital Basal Thermometers

About 52% of Symptothermal Method users use a digital basal thermometer with two decimal places, as only these provide a sufficiently high accuracy. It has the advantage over the analogue basal thermometer that it is break-proof and reliably stores measured values. However, a digital basal thermometer can only be preserved for about a year, as the accuracy will wear off over time. This is relatively unimportant for the desire for childbearing because 81% of the Symptothermal method users get pregnant within six months. The measured values must be rounded off for the documentation in a cycle sheet (ex: 36.38 °c → 36.40 °c | 36.37 °c → 36.35 °c), often this round off is already automatically taken over by a cycle software or a Symptothermal Method App.

Geratherm 4019000065 Gt-3230 digital

Geratherm Digital basal thermometer

Geratherm Digital with flexible tip © Geratherm Medical AG

The most popular digital basal thermometer on our blog is the *Geratherm digital. It is probably so popular because it can save up to Ten temperature values! All other comparable digital Symptothermal method basal thermometers can only save the last temperature value. Storing more than one value is very useful if you want to document the entry of the values in a Symptothermal method App a few days later. This has often happened to me so much so that I can hardly remember the values of yesterday and the day before yesterday. It is also great that the beep sound is very quiet compared to other Symptothermal Method Basal thermometers and your partner can sleep undisturbed in the morning. The flexible tip makes oral measurement even more pleasant compared to basal thermometers with a rigid tip. This is especially important at the beginning, as most Symptothermal Method users start with the three-minute measurement in their mouths. Contrary to the customer review at Amazon, the basal thermometer continues to measure for up to 9 minutes after the beep sound. So just continue to measure after the beep until the three minutes are over, then you will also get comparable temperature values. But the absolute best feature in comparison with some other Basal thermometers is probably the illuminated display, which makes it really much easier to read the values when it is dark outside and you have to get up early. The Geratherm digital is totally easy to operate with just one button. Overall, Geratherm digital is for me in the price-performance ratio, the best digital Symptothermal Method Basal Thermometer on the market. It was delivered to me perfectly by Amazon and measured very reliably.

Analogue Basal Thermometers

About 31% of Symptothermal Method users use an analogue basal thermometer, according to a Survey from the Symptothermal Method Forum in Germany with more than 800 women. Analogue Symptothermal Method basal thermometers have the advantage that they are theoretically durable and can last a lifetime and do not require a battery. Their Disadvantage is that they can easily break because they are made of glass.

Geratherm Mercury Free Oral Glass Thermometer

By far the most popular analogue basal thermometer is the *Geratherm Mercury free oral glass basal thermometer. It is one of the few analogue basal thermometers that can measure both in degree Fahrenheit °F and in °C. It also has an appealing design and a help with which the basal thermometer can be easily shifted down with the right technique. I also find the scale sufficient to be able to read the values well.


iButton Basal Thermometer The iButton is a special basal thermometer in the form of a microchip. With the iButton, women can measure their body temperatures in their sleep and then transfer the measured data to their PC. The iButton is programmed in such a way that it measures at certain time intervals. Nevertheless, there are many good testimonials about this device, so that the iButton is used by about 7% of the Symptotheremal Method users. We can recommend the iButton set from EndoTherm because I have tested it.

Frequently asked questions about measuring basal body temperature

Which basal thermometer is best suited for the Symptothermal Method?

Digital basal thermometers with two decimal places and analogue Symptothermal Basal thermometers have been proven to achieve the same level of safety when evaluating the basal temperature curve and are generally compliant with the regulations. When buying, it is advisable to consider the pros and cons of each basal thermometer and weigh it with your own needs. The iButton is not yet sufficiently well studied to make a statement, yet there are many positive experiences with it.

Where can the basal temperature be measured?

The basal temperature can be measured in the mouth (oral), in the Vulva (vaginal) or in the anus (rectal) immediately after waking up and before getting up. Before the measurement, the woman must have rested for at least one hour.

Can I change the measuring location as well?

Yes, but only at the beginning of a new cycle can the measuring location be redefined and then maintained for at least as long as the cycle is evaluated.

How long must the basal temperature be measured?

The measuring time for the digital and analogue Symptothermal Method basal thermometer is three minutes. The digital thermometer continues to measure after the beep sound until the three minutes have been reached.

What do you need to consider when measuring basal temperature?

Do not change the Symptothermal Method basal thermometer within a cycle if possible. The cycle evaluation can only be carried out by temperature values measured with one and the same thermometer, because there may be deviations between the thermometers – even if it is technically the same product. We recommend you to read prior to the Symptothermal Method application, our ebook “When Am I Fertile? The natural way to conceive”.