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Before You Buy a Basal Body Temperature Thermometer

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Updated February 18, 2012

Basal body temperature thermometers are marketed and sold specifically for women trying to get pregnant. While I think 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

The companies that sell BBT thermometers try to convince buyers that using a fancy thermometer will get better results, helping you get pregnant faster. Except the thermometer doesn't help you get pregnant, but timing sex for ovulation. (And that’s only if other problems aren't getting in the way, like infertility.)

Often, 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. Except all you need is an accurate reading to the tenth degree, which is available on most thermometers.

What to Look For When Buying a BBT Thermometer

All this being said, some features I can appreciate in BBT thermometers. On digital BBT thermometers, memory recall is a nice feature. This means that after you shut off the thermometer, when you turn it on again, it will tell you what the last recorded temperature was.

A beep to indicate that the thermometer is finished is also 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. (I have!) The beep helps.

Also, a must in a BBT thermometer is accuracy to 1/10th of a degree. Two-tenths is not good enough for charting.

Should You Buy a Glass or Digital BBT Thermometer?

Something else you should consider is whether you want a digital or glass thermometer.

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 (when used daily, more often than you might imagine).
  • 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.

What to Pay for a BBT Thermometer

I’ve seen BBT thermometers being sold for as much as $60, but the average price for a basic BBT thermometer is about $12 to $15.

If you’re buying a digital thermometer, I wouldn’t spend more than $15, and you can spend $10 and still get a good-enough thermometer.

If you’re buying a glass thermometer, $10 or less is a good limit. You want one that is non-mercury, but 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 BBT charting.

Which BBT Thermometers Should You Avoid

Before you buy, I’d read reviews online, but not because of the fertility features. Many cheap digital thermometers don’t last long or don’t have easy to read displays (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, and the really expensive thermometers will track your temperature for you, on an internal computer. In my opinion, these features are a waste of money. You can find free fertility charts for tracking your BBT, or sign up for a free fertility calendar service online.

So, Which BBT Thermometer Should You Buy

You don’t need a thermometer that is called a “BBT thermometer,” but you should consider which features you want (like memory recall) or whether you want glass or digital. The most important feature to look for is a thermometer that is accurate to 1/10th of a degree.

Whatever you decide to buy, remember that the thermometer won't help you get pregnant -- it’s timing sex for ovulation, which you can do in a number of ways. BBT charting is just one option, and a fancy BBT thermometer or monitor will not magically help you get pregnant.

More on how to get pregnant:

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