The best breathalyzers of 2024

The BACtrack Trace is the best breathalyzer I tested. It consistently delivers readings as precise as the more expensive, high-accuracy breathalyzers. Once I turn it on, it takes roughly 11 seconds to prepare for use, and it delivers results within a few seconds as well. This means you won't be stuck staring at the screen for long. At $100, it's a great value for the price, too.

Its main drawback is that it needs to be sent back to the manufacturer for calibration every 6 to 12 months to maintain its accuracy. This depends on how frequently you use it, but almost all breathalyzers require this step, so I can't count it against the Trace.

BACtrack describes this model as having "police-grade accuracy," and all sources seem to agree. The S80 has glowing reviews from customers and other publications, and it proved its reliability and accuracy during our tests as well.

If you're using a breathalyzer as a parent, this is the model you should invest in to be as fair as possible. Plus, it's quick: The device warms up in under 15 seconds and delivers a BAC reading within 3 seconds. This proved extremely helpful when testing multiple people.

The C6 is conveniently designed as a keychain, so you'll always have it on hand when you're wondering if you're ready to leave a dinner party or should hang out for a while longer. Even smaller than the BACtrack Mobile (see below), the C6 also estimates your ZeroLine to tell you how long till you're likely at 0.00%.

The device can also connect to your phone to store all breathalyzer readings, as well. The feature isn't mandatory, though, so if your phone is dead, or you just don't want to use it, it can still operate on its own and simply display the BAC reading on its built-in screen.

Also convenient is the fact that the C6 warms up quickly, in just about five seconds. And being one of the cheaper products we tested, it's good value for the money. The trade-off is that the C6 isn't quite as accurate as the more professional devices, but the difference is marginal and unlikely to change anything in practice. All things considered, this is the best portable breathalyzer on the market.

Because our prior budget recommendation, the AlcoHAWK Ultra Slim Breathalyzer, is no longer available, you may want to consider the C6 as a budget option. The downside is that the C6 isn't as accurate as the Ultra Slim. Another suggestion is the BACtrack Go, which is priced under $50. Although we haven't tested this model, BACtrack's products are notable for their quality, but customer reviews for the BACtrack Go aren't as positive as we would like. 

The BACtrack Mobile connects to your smartphone via Bluetooth, so it automatically logs your results, which is useful for those looking to monitor their alcohol consumption habits over time. It's easy and intuitive to set up and use, and the device is rechargeable so you don't have to worry about swapping out the batteries.

Unfortunately, this doesn't have a display, so you will need to use the app to see your results. If you don't have a smartphone or don't want to rely on one, I recommend opting for a different model. Keep in mind that if your phone is dead, you can't use the breathalyzer.

Based on my tests, this device is also highly accurate and comparable to other BACtrack models. The Mobile is considerably smaller than most of the other breathalyzers on this list, which can be convenient for slipping into a purse or pocket.

Using the app also provides you with another piece of information: your "ZeroLine," which is an estimate of how soon your BAC will return to 0.00%. It should be noted that people process alcohol at very different rates. Things like their size, what they've eaten that day, and other individual factors play a part, so while the ZeroLine offers a general timeline, you'll want to confirm-test your BAC again before driving.

We narrowed it down to six well-received models based on our criteria on how to shop for a breathalyzer (see below). To test each of the best breathalyzers for accuracy, I consumed exactly one standard drink (5 ounces of wine) and then measured my BAC on each device after 30 minutes. I then measured again after another 30 minutes. I repeated the entire process the following day to guarantee there weren't any flukes.

All data was evaluated for any statistically significant outlier readings. The highest accuracy devices were those that produced the fewest anomalous readings.

Note: Despite drinking the same standardized amount for Test 1 and Test 2, my BAC reading was different between the days. This could be due to a variety of factors, like what and when I ate before testing. What's important is comparing Test 1's tests among the different breathalyzers and seeing if those discrepancies were repeated with the same brand on Test 2.

Although only a handful of companies make breathalyzers for the general public, many of them have significant differences. Before purchasing one of the best breathalyzers, it's important to consider:

Price: The cheapest product I tested was roughly $40, while the most expensive was $131. Generally, the more expensive breathalyzers tended to be more accurate, but you don't need the same level of detail for personal use as a police officer.

Accuracy and reliability: Almost all major breathalyzer makers claim their products are either "professional" or "police-grade" in terms of accuracy. This can make it hard to determine which deliver on that claim. Since accuracy is vital, I conducted different tests around the accuracy of each device to tell you which ones live up to their price tag. Ultimately, I discovered that price does not indicate reliability.

Result readability: Some breathalyzers can display a BAC reading directly on the device, while others rely on an optional or mandatory Bluetooth connection with a smartphone. Using a smartphone can be helpful if you intend to store results in a custom database. If you don't have or don't want to use a smartphone, a standalone device is your best option.

Calibration and charging: Many breathalyzers need to be recalibrated after 6-12 months for the device to continue to accurately read BAC levels — and this has to be done by being sent back to the manufacturer. Some models do allow you to replace the sensor yourself, though that does require some know-how of the device. It's important to consider what kind of batteries a breathalyzer requires and whether it's rechargeable or not.

Do personal breathalyzers work?

First, it's worth acknowledging that breathalyzers are fallible, and results can be affected by operator error (the user) as well as technical issues. This is partially why breathalyzer BAC readings, on their own, are considered inadmissible trial evidence in some states. But high readings from a personal device should never be shrugged off as a false positive — if there's any indication that you're not sober, don't get behind the wheel.

How do you use a breathalyzer?

To be safe, measure your levels after 30 minutes and then again after 60. If your BAC is higher at the second reading, wait another 30 minutes before taking another reading.     

Timing matters a lot. The manufacturer's instructions for all the products we tested say to wait about 20 minutes after eating and drinking to use the breathalyzer since it takes time for alcohol to be absorbed into a person's system after consumption. However, because people's bodies metabolize alcohol at different rates, measuring at 20 minutes isn't always going to produce the most accurate results.

Depending on your physiology, what else you've had to eat or drink, and timing, among other factors, your BAC could very well keep increasing even after a 20-minute wait.

Do breathalyzers work for everyone?

Certain groups of people are more likely to blow false positives, namely diabetics and those on low-calorie or ketogenic diets, as the presence of ketones in one's breath will interfere with the reading.

In addition to research, for this article, I spoke with Dr. Shannon Sovndal, MD, FACEPS, who is a board-certified doctor in emergency medicine and emergency medical services (EMS).

He is a fellow of the American College of Emergency Physicians and has worked extensively in pre-hospital medicine, the fire service, and tactical medicine. He is currently the medical director for multiple EMS agencies and is the author of three books, including, "Fragile."