Best breathalysers 2025
We test six units that claim to see you if you’re below drink-drive limits
Getting behind the wheel after drinking even a small amount of alcohol is always a bad idea and something we would never condone. But drinks affect people differently and it is not easy to judge if you are safe and legal to drive after consuming alcohol in moderate amounts or hours before.
It could be the morning after a party, for example, or if your teenager calls to say that they’ve missed the last train home when you’ve had a glass of wine with your dinner. In these situations, you can use a breathalyser to check if you are safe and legal to drive. These will either give you peace of mind or make it clear that you should be calling a taxi.
For this test, we looked at reusable electronic devices rather than the disposable bags. There are two general types we tested – those that use semi-conductors, which are cheaper but tend to be less accurate, and others with fuel cells, which are pricey but more precise. We evaluated both types here.
How we tested
While the temptation is to test these devices by having a few pints in the pub and seeing if they detect it, we needed a more precise method. So we used breathalyser maker AlcoSense’s lab to conduct our tests under strict controls.
To ensure there was no bias, we secured sealed and certified breath alcohol simulation solutions from an independent supplier and randomly chose two of AlcoSense’s devices for the tests from its warehouse.
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Cash £10,000We then followed the devices’ instructions and ‘blew’ into them using special machines that deliver a precise dose of alcohol in air to replicate a human’s exhaling lungs. Reference readings were recorded using a suitcase-sized police evidential breathalyser to double check accuracy.
Each device was tested five times at both the Scottish 0.22mg/l limit and then again at the 0.35 mg/l for the rest of the UK.
AlcoSense Excel
- Rating: 5.0 stars
- Price: around £99.99
- Type: Fuel Cell
- Contact: alcosense.co.uk
Although it doesn’t have quite as many features as the Pro, the Excel’s sub-£100 price will make it a more viable purchase for many drivers who just want to check themselves once in a while.
It makes the process simple. Slide the face upwards to reveal the blow hole, follow the instructions on the colour screen and the Excel will tell you clearly if you are legal to drive. It was consistently accurate and makes some more expensive rivals look old-fashioned and embarrassingly inaccurate.
AlcoSense Pro
- Rating: 4.5 stars
- Price: around £149.99
- Type: Fuel Cell
- Contact: alcosense.co.uk
While it looks similar to the winning AlcoSense Excel, the Pro has a larger fuel-cell sensor that should result in slightly more accurate readings. It is also helped by a blowing guide, which helps you get the right quantity and flow of breath into the machine.
A more sophisticated menu allows you to change your location to adjust the limits for anywhere in the world with a pre-loaded (and updateable) database of legal levels. We also like the ‘time to sober’ estimate that is shown with your results. As with the AlcoSense Excel, the Pro’s results were consistently accurate.
AlcoDigital Platinum
- Rating: 4.0 stars
- Price: around £189
- Type: Fuel Cell
- Contact: breathalyzer.co.uk
The AlcoDigital lacks any sophisticated menus, but still has a simple testing procedure which is easy to understand. Turn it on, insert a tube and wait for the simple display to tell you to blow, and a measurement will quickly pop up, listed in mg/l.
The results were well within tolerance levels, although it did under-read very slightly compared with the police-spec machine’s results at the English and Welsh limit. As with speedometers, we think it’s best to err on the side of caution when your driving licence is at stake.
AlcoSCAN CA20
- Rating: 4.0 stars
- Price: around £169.20
- Type: Fuel Cell
- Contact: arco.co.uk
The CA20 is bigger than its rivals in this test and is supplied in an impressive protective case. Although the screen looks old- fashioned compared with the AlcoSense pair, it changes colour to tell you if you’ve failed based on pre-set limits. It was accurate at the Scottish level, but under-read consistently by 1.4mg/l at the English/Welsh limits.
AlcoSCAN’s unit looks expensive compared with our winners, too, and the £92.99 annual recalibration check is more than three times the cost of an AlcoSense (£29.99).
AlkoSure F16
- Rating: 2.5 stars
- Price: around £83.99
- Type: Fuel Cell
- Contact: drugtests.co.uk
At £83.99, the AlkoSure is good value for money for a fuel-cell sensor device. Although it looks basic, the F16 can store the results of up to 50 tests and it’s simple to switch between different measurement types.
But it consistently under-read compared with our calibrated samples, showing an average of 0.19mg/l at the evidential breathalyser’s calibrated reading of 0.224. At the higher limit, the five test readings varied widely between 0.29 and 0.35 against a calibrated 0.354.
Vtizikl Breathalyser
- Rating: 2.0 stars
- Price: around £15.99
- Type: Semi-conductor
- Contact: amazon.co.uk
The Vtizikl looks great value, at £15.99. It uses a semi-conductor sensor to keep cost down and is also rechargeable to save spending on batteries. It’s tiny compared with the others in the test, being about the same size as a cigarette lighter. With no blow tube, it is easy to get the breath dosing wrong, however, and the results varied wildly. It will sense alcohol on breath, but can’t be relied upon for an accurate result.
Verdict
The AlcoSense devices were consistently accurate in all our tests, made it easy to see if it was legal to drive, and made rivals look complex and overpriced. They take both first and second places here. Of the other units here, the AlcoDigital Platinum gave results within tolerance levels, but it looks expensive and basic compared with the winning AlcoSense Excel.
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