What to Know Before You Buy a Basal Body Thermometer

What You Need, What You Don't, and Considering Extra Features

Digital basal body temperature thermometers
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Basal body temperature thermometers are marketed and sold specifically for women trying to get pregnant. While charting your basal body temperature (BBT) is a good way to track ovulation, one of the biggest benefits to this method is the low expense.

So, why spend more than you have to on a BBT?

What BBT Thermometer Manufacturers Promise Customers

Will a fancy thermometer help you get pregnant faster? Eh... it's unlikely. The key to getting pregnant is timing sex for ovulation. (That’s only if other problems aren't getting in the way such as infertility, of course.) You don't need a fancy thermometer for that.

BBT thermometers will boast that they are accurate to 1/100th of a degree. For example, the reading will give you 98.63 F instead of only 98.6 F. However, all you need is an accurate reading to the tenth degree. This is available on almost every basal body thermometer.

What to Look for When Buying a BBT Thermometer

With all that said, the specialty BBT thermometers do have features worth getting. Digital BBT thermometers frequently have memory recall. This means you don't have to record your temp first thing in the morning. You can just turn the thermometer back on to get the last recorded temp.

A beep to indicate that the thermometer is finished is nice. When you’re taking your temperature before you’ve stepped out of bed, it’s easy to fall asleep with the thermometer in your mouth. The beep helps. A must-have in a BBT thermometer is accuracy to one-tenth of a degree. Two-tenths is not good enough for charting.

Pros of digital thermometers:

  • They are easier to handle.
  • You don’t have to remember to shake it down the night before.
  • It won’t shatter on your bathroom floor.

Cons of digital thermometers:

  • The batteries need to be replaced. (More often than you might imagine, when used daily.)
  • You may get inaccurate readings for the month or so before the batteries start to die.
  • Sometimes they stop working for no good reason. Sometimes after a few years, but sometimes after only a few months.

Choose whichever appeals to you most. Just make sure you stick to the same thermometer over a month's time.

What to Pay for a BBT Thermometer

There are BBT thermometers being sold for as much as $60. That said, the average price is about $20 to $30. If you’re buying a digital thermometer, you don't really need to spend more than $30. You can spend just $10 and still get a good-enough thermometer. It may not have all the features, though.

If you’re buying a glass thermometer, $10 or less is a good limit. For glass, you want one that is non-mercury. You don’t need one that is specially made for fertility. As long as the thermometer is easy to read to the 1/10th of a degree, it’s good enough for charting.

Which BBT Thermometers Should You Avoid

Before you buy, read some reviews online. Not because of the fertility features, but because many cheap digital thermometers don’t last long or don’t have easy to read displays. (This is important if you don’t have memory recall functions and need to read it in the dusk of the morning.)

Some BBT thermometers come with sample charts. The really expensive thermometers will track your temperature for you on an internal computer. You may or may not consider these features as a waste of money. It depends on how comfortable you are with charting.

You can find free fertility charts for tracking your BBT. You can also sign up for free fertility calendar services online. There are many fertility apps for your phone, too. The best ones have web-based and phone-based features.

So, Which BBT Thermometer Should You Buy?

If you're not ready to buy a new thermometer now, you might be able to get by with whatever you have at home.

However, if you do want to buy a new one, these basal body thermometers are reasonably priced and have good features.

Smart Basal Thermometer by Femometer

Features include: 

  • Accurate to 1/100th of a degree
  • 300-day memory
  • 90 second read time 
  • Will sync to your phone via Bluetooth for ovulation prediction

i-Snow Med Multi-Function Digital Basal Thermometer

Features include:

  • Accurate to 1/100th of a degree
  • 60-day memory
  • Back-lit display for early morning readings
  • Built-in alarm to help you remember when to take your temperature 
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  1. Parenthood P. What is the Temperature Method?: Basal Body Temperature. Planned Parenthood.

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