The 6 Best Keychain Breathalyzers
We spent 25 hours on research, videography, and editing, to review the top selections for this wiki. Driving under the influence of any intoxicant is never a good idea. While the compact keychain breathalyzers on this list should definitely not be relied upon to guarantee you are sober enough to get behind the wheel, they can provide an indication that it's probably wise to open up that app and order an Uber or Lyft to get home. When users buy our independently chosen editorial picks, we may earn commissions to support our work. Skip to the best keychain breathalyzer on Amazon.
6. Keychain Alcohol Tester
The Keychain Alcohol Tester may use an advanced semiconductor oxide alcohol sensor to detect booze in breath, but it displays the results in a decidedly basic way: a green light means you're alcohol-free, a yellow light indicates a bit of booze breath, and red means drunk.
- built-in flashlight
- very low price tag
- results far from specific
|Rating||4.1 / 5.0|
5. TruBreez FIT
The TruBreez FIT is a rather low-cost yet relatively accurate BAC testing unit, and it is so simple to operate that even a user well into his or her night will figure out how to initiate a self test. The screen can be hard to see in low light conditions, however.
- come with travel case
- bright white so hard to misplace
- occasional false positives
|Rating||4.5 / 5.0|
4. O-Best Professional
The O-Best Professional is small enough to be tucked into a change pocket, or will add only minimal weight and bulk to your keychain, so there's no excuse not to take this device along when you and your friends go out for a night of carousing.
- auto power shutoff
- fold-out mouthpiece
- inaccurate immediately after drinks
|Rating||3.9 / 5.0|
3. Greenwon Alcohol Analyzer
The Greenwon Alcohol Analyzer has an effective test range between a BAC of 0.0 percent and 0.19 percent, though you should use the reading this unit provides as a guideline to help direct your behavior and not as an ironclad guarantee that you're sober enough to drive.
- great for novelty use
- affordable price point
- ergonomic design
|Rating||4.8 / 5.0|
2. Vio Smartphone
The Vio Smartphone unit syncs with your iPhone or Android phone or tablet to provide you information about the amount of alcohol in the blood of the user. Its paired app removes ambiguity that other self-contained units can create, clearly displaying precise results.
- comes with drink log
- offers advice on intoxication levels
- estimates time to zero blood alcohol
|Rating||4.9 / 5.0|
1. BACtrack Keyring Breath Alcohol Tester
The BACtrack Keyring Breath Alcohol Tester shares its results mere seconds after its user exhales, displaying the detected Blood Alcohol Content reading on its compact but crystal clear red-on-black LCD screen. You'll be able to read the numbers even after multiple drinks.
- available in several colors
- one-touch operation
- average of 75 tests per battery
|Rating||4.8 / 5.0|