Updated January 2022
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Buying guide for Best breathalyzers

A breathalyzer can be a fun form of entertainment at a party, or it can keep you and other guests safe. By measuring someone’s BAC, you may be able to convince a friend to hand the keys to someone else. Breathalyzers come in different types and will vary in their dependability, so you should consider models carefully before making a purchase.

Disposable one-time-use models can only be relied on to tell whether someone has been drinking. Semiconductor designs provide a more dependable BAC reading, though fuel cell sensor units are the best option for long-term reliability and accuracy. Active breathalyzers are blown into, while the less accurate passive breathalyzers are blown across. More accurate models tend to come at a higher price, and you should consider the additional cost of new mouthpieces and batteries. Recalibration can also become costly.

Breathalyzers are made to be easy to use. After all, the people using them may not have their full mental faculties after drinking alcohol.

Perhaps seeing a BAC number on a screen would convince someone not to drive after drinking.

Breathalyzer types

Three types of breathalyzers are available for personal purchase. These aren’t quite the same units that law enforcement uses, but they provide relatively accurate readings most of the time.

You do have to perform proper maintenance of the unit over time, including recalibrations.

Fuel cell sensor units

A fuel cell sensor unit provides the most accurate readings possible in a personal breathalyzer. It does require occasional recalibration, which adds to your overall expense.

Fuel cell sensor units have a higher starting price than some other designs, too. In a fuel cell breathalyzer, the unit measures the concentration of alcohol molecules in the breath of the user. The BACTrack S80 Pro, our Best of the Best product, employs this technology.

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Did you know?
A breathalyzer can perform anywhere from 200 to 1,000 tests before needing recalibration. It depends on the model.

Semiconductor oxide sensor units

A personal breathalyzer with a semiconductor oxide sensor is considered a “basic” unit. These devices are small and may even fit on a keychain. But they aren’t quite as accurate as fuel cell units, and they may need recalibration more often than other designs. The TruBreez 2020, our Best Bang for Your Buck option, uses this technology.

Disposable units

You may have seen these cheap breathalyzers in liquor stores. They’re designed for one-time use and then must be thrown away. These units will indicate whether someone has been drinking alcohol, but their accuracy is not dependable.

"Although there are plenty of charts that help you calculate your BAC, they aren’t accurate for every person."

Design and use

When it comes to actually using the breathalyzer, two designs exist.

Active breathalyzers

To use an active breathalyzer, you must exhale into a plastic mouthpiece. The unit measures the concentration of alcohol in your breath. By placing your mouth directly over the mouthpiece, you ensure that no outside contamination of the air occurs.

Breathalyzers at the mid- or upper-range price point often use an active measurement system. Fuel cell breathalyzers also use this design.

"Are you looking for a budget-priced breathalyzer? You may wish to consider a passive unit, as these tend to cost less."

Passive breathalyzers

To use a passive breathalyzer, you place your mouth within an inch of the mouthpiece and blow across it. The unit measures the concentration of alcohol in your breath.

Unlike an active unit, a passive breathalyzer could potentially suffer contamination from the outside air.

Why it works

A breathalyzer is able to work because of the way the body processes alcohol.

  • Alcohol is absorbed into the bloodstream from the stomach, intestines, and mouth. The alcohol molecules do not change during this absorption process. The blood then carries these molecules throughout the body.

  • The molecules eventually reach the lungs and are expelled as the person exhales. This is why you’re often able to tell whether someone has been drinking by the smell of their breath. Alcohol molecules add a distinctive odor to the breath.

  • The concentration of alcohol in the lungs closely matches its concentration in the bloodstream. So by measuring alcohol concentration when a person exhales, the breathalyzer is able to provide a relatively accurate BAC number.

Breathalyzer prices

Budget breathalyzers

A budget breathalyzer will probably cost less than $20. This type of unit may be disposable, or it may fit on a keychain.

In general, these tiny units are more like toys than precise measuring instruments. In other words, don’t expect to receive a precise reading from a budget breathalyzer. These units are designed for general alcohol detection rather than BAC accuracy.

"Some breathalyzers that fit on a keychain may be able to connect with a smartphone app to give you data."

Mid-range breathalyzers

Expect to spend between $20 and $50 for a mid-range personal breathalyzer. Most of these are handheld units that are easy to use, although BAC accuracy is hit-and-miss.

A mid-range breathalyzer may require more frequent recalibration that its pricier counterparts.

"Desktop breathalyzers aren’t portable. This is the type of unit you might see at a police station. A desktop breathalyzer may use electrochemical fuel cell technology or infrared spectrophotometer technology."

Top-range breathalyzers

You could spend anywhere from $50 to $200 on a top-tier personal breathalyzer. With proper maintenance, these units tend to provide relatively accurate BAC readings. They cannot exactly match what law enforcement can measure, but they can give you a good idea of your BAC.

The Best of the Best choice in our product list, the BACtrack S80, falls within this price range at a cost of $129. As of this writing, it is the most accurate device on the market.

Other costs

If you plan to use your breathalyzer regularly, your initial expenditure won’t be your only expenditure. Expect to shell out a little money on breathalyzer maintenance, too.


You’ll want to replace your breathalyzer’s mouthpiece after each test. It’s more sanitary, and it eliminates the possibility of cross-contamination from a previously used mouthpiece. Cost varies from unit to unit, but you can expect to pay between $0.40 and $1 for each new mouthpiece.

"If you notice that your breathalyzer is giving you consistently incorrect readings, it may need to be recalibrated."


A personal breathalyzer runs on battery power, and these batteries must be replaced from time to time.

Fortunately, a breathalyzer doesn’t require a lot of power to operate, and you probably won’t need new batteries more than once every several months.

"The BACtrack Trace Professional Breathalyzer in our product list is one of the best units on the market in terms of battery life."


After a certain number of uses, most personal breathalyzers must be recalibrated. To do this, you’ll need to send the unit back to the manufacturer.

The cost of recalibration generally runs between $15 and $50. (You may be able to recalibrate some units yourself with the right parts from the manufacturer.)

Each unit has a different recalibration schedule; some need recalibration after every 200 uses, and others need it every 1,000 tests. To ensure accuracy, it’s always best to check with the manufacturer.

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Did you know?
Some higher-end units will keep a running displayed count of the number of tests performed. This can help you figure out when a recalibration is needed.


  • Because so many factors can affect the accuracy of a reading, it’s impossible to say that these units are 100% precise. We liken these units to a thermometer strip you’d place on an infant’s forehead. The strip gives you a relatively accurate idea of the infant’s body temperature, but it’s not as accurate as the process a doctor would use to take the infant’s temperature.

  • With most personal breathalyzers, you have to wait 15-30 minutes without taking a drink before testing.

  • Keep extra mouthpieces on hand to allow different people to use the device.

  • Some breathalyzers don’t work if the surrounding temperature is below freezing. So don’t keep one in your car on a winter night and expect it to work.
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Having a back-lit display is nice when you’re trying to read the display outdoors at night or in a dimly lit bar.


Q. Can I rely on a personal breathalyzer to be precisely accurate?
With the exception of budget-priced disposable and keychain models, personal breathalyzers are fairly accurate. They don’t provide the same level of accuracy as a law enforcement breathalyzer, but they come relatively close in terms of BAC measurement.

Q. Why would I want a breathalyzer? Drinking and driving shouldn’t happen, so why would I measure this number?
We agree you shouldn’t be using a personal breathalyzer to determine whether you’re sober enough to drive. If you’re questioning your sobriety, it’s time to call for a ride.

If you have a personal breathalyzer, though, it may help you talk a friend out of driving after a few drinks. On the flip side, some people may want to use a breathalyzer to prove they haven’t been drinking. For example, if you’ve had problems with alcohol in the past, you can use this device to show you’re sober.

Measuring your BAC at home also can help you learn more about how alcohol affects your body.

Q. How easy is a personal breathalyzer to use?
Although each breathalyzer design is different, most follow a similar usage pattern. Insert a fresh mouthpiece on the unit and press the start button. After the warm-up period, which can last 15-45 seconds, you’re ready for a test. The Pro-Tec Breathalyzer X2000 Professional Grade in our product list has one of the shortest warm-up times at about 15 seconds.

Some units will give you a countdown until the warm-up period is completed. Inhale deeply and exhale into the mouthpiece. Depending on the unit, it may take 5-10 seconds of steady exhalation to receive a reading. Most breathalyzers will give you an audible signal when you can stop exhaling. You’ll then receive a BAC number within several seconds.

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