How to calibrate breathalyzer and what is calibration?

­How to calibrate breathalyzer and what is calibration?

Calibration is the process of checking results of the device with results provided in the model template. Through calibration internal settings of the breathalyzer (sensor) are checked and adjusted by comparing and adjusting its test results to a known alcohol standard.

­Breathalyzer calibration


How to calibrate a breathalyzer?

Calibration has to be performed in appropriate conditions (in terms of temperature, humidity, flow force, fixed alcohol content, etc.) and by trained technicians. It is not an easy job. In order to perform calibration technician needs to set a breathalyzer to the calibration mode, it is done with the use of specially designed pin tools. Next it is connected to calibration devices. During this process air in quantity similar to a human exhalation with predefined alcohol content is pumped into it.

When should you calibrate your breathalyzer?

  • Calibration should be performed once per 100-500 tests or every 6 months, depending on the type of breathalyzer, sensor used and manufacturer’s specifications.
  • If a person has been drinking alcohol and the device shows 0.00‰.
  • If the test was done right after alcohol consumption. High concentration of alcohol in the exhaled air may lead to permanent damage or decalibration.
  • If CAL or SER notice is displayed.
  • If the breathalyzer has been stored for a long time with materials containing alcohol.
  • If after performing a few tests in similar periods of time the result is the same (it should be lower).
  • There is no reaction after performing a test or counting time to start a test.
  • It repeatedly provides unusually high test results or even goes beyond the maximum.
  • If in between short periods of time the results are very different.

How does calibration equipment look like?

Breathalyzer calibration - process
How to calibrate a breathalyzer?

See the calibration process

Professional breathalyzer calibration.

Are there breathalyzers that do not require calibration?

Such devices can be found on various auction sites, non-branded stores with breathalyzers etc. These are cheap, disposable devices of doubtful effectiveness. Many Chinese companies sell very cheap breathalyzers that cannot be calibrated due to sensor used. Thus once it is decalibrated, you need to buy a new device. So you not only waste money but also cannot trust its results. Price is not the only factor as some Chinese fakes can cost as much as renowned devices. We saw breathalyzers that produced ridiculous results, as without drinking any alcohol the result was 0.23‰! Or our volunteer had 0.2 and the device showed 0.00. Remember that the alcohol limit for driving in the UK is 0.8‰.

We would also like to turn your attention to various opinions, analyses and tests conducted by some stores. Usually they want to advertise the most profitable products and not the ones with very good results. Thus you need to think twice before choosing a store and breathalyzer that you can trust.


Calibration in Detective Store costs 25 GBP (depending on the model). Check our price list.

How to secure your breathalyzer from damage and decalibration?

  • Before taking the test rinse your mouth with clean water.
  • Control and calibrate your device as per manufacturer’s recommendations.
  • Monitor battery usage, use only alkaline branded batteries.
  • Do not perform the test straight after drinking alcohol. Take at least 30 minutes break. Otherwise the result may be false or you can even damage the device.
  • Do not smoke before the test nor exhale the smoke to the mouthpiece. It can damage the sensor or make the breathalyzer decalibrate.
  • Do not keep it in your car, especially during winter time, as sensor is sensible to extreme temperatures.

Remember – drinking under influence may have very serious consequences!
You can lose your driving licence, your health and even life. Be responsible for your actions and the life of others. Test yourself before setting off for a drive.

Breathalyzer calibration in Detective Store