What is a calibration certificate and do I need one?

5 min read
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Qu'est-ce qu'un certificat d'étalonnage et en ai-je besoin ?
what is a calibration certificate ? why do you need it? Is it a legal obligation? We answer all these questions and more to help you understand everything you need to know about calibration certificates.

We also reviewed one of our UKAS certificates to understand what everything in it really means. In France, the reference certificate is the COFRAC. UKAS certificates are 100% equivalent COFRAC and are accepted by inspection bodies.


A calibration certificate is a official document certifying that your thermometer has undergone a calibration test in an accredited laboratory. The date, the method and the results of the test are indicated on the certificate.

The calibration test compares your thermometer readings with a traceable device or one reference thermometer.

This documentation proves the precision of your thermometer. If the results show that the thermometer is inexact, he should be recalibrated. You will receive new documentation to show this.


Calibration certificates are not a legal requirement in France. In catering applications, your plan HACCP determine how and when your business should calibrate your thermometers.

However, a calibration certificate is the only legal document that proves that your equipment is exact. There are several advantages to this:

  • A calibration certificate can be used in front of a tribunal in case of health problem and security related to a dangerous temperature.
  • Calibration certificates are useful for visit EHO and others inspections or audits.
  • Make sure your thermometers are calibrated with a high level of precision will preserve the quality and the security of your temperature controls.


When a thermometer undergoes a calibration, its readings are checked against a reference thermometer. The reference thermometer must have already undergone a calibration test using an even higher standard than the current one.

Each time a device undergoes a calibration test using a thermometer that has been calibrated to a higher standard, it forms a chain. When this string is uninterrupted and returns to the highest reference thermometer of a national calibration center (or equivalent), it becomes traceable.


UKAS is UK's national accreditation body. When UKAS accredits a laboratory, its testing is carried out to the highest standards in the country.

Many other countries have their own accreditation bodies that administer their national standards. The NIST is responsible for this United States.

We have an accredited calibration laboratory UKAS for measurements of temperature and humidity. Customers can send us instruments for UKAS calibration.


A certificate traceable means that your thermometer has been tested against a reference thermometer in the chain of custody.

A certificate UKAS means that your thermometer has been tested in a UKAS accredited laboratory.

A traceable certificate is often satisfying for the EHO and other inspectors who may want to verify your calibration procedures during visits. A certificate UKAS will give you extra peace of mind that your thermometer has been calibrated to the highest standards United Kingdom.


Below you will find a example of certificate from our UKAS laboratory. Read the key to learn more about each section.

To date which the calibration certificate was issued.

B. Yes number of unique certificate.

Key logo UKAS Calibration Official; this shows that the certificate is traceable to the UK national standard. The number under the logo is the code unique from the UKAS accredited laboratory. Details of company accreditation can be found on the UKAS website.

D. Address and contact information from the calibration laboratory.

AND. Last name and signature of the person who performed the calibration.

F. Last name and customer address.

G. Order number.

H. Reference number.

I. Date at which the instrument is come in the lab and date at which the calibration was ended.

J. Ambient temperature and humidity in the laboratory during the test.

K. The international temperature scale of 1990 – (ITS-90) is a temperature scale used by laboratories to measure calibrate the thermometers. Temperatures are determined by holding substances, such as water, mercury, and tin, under conditions where they will maintain a specific temperature. Using these standards allows laboratories to be confident of the temperatures they use to test thermometers, providing a high level of accuracy.

L. Thermometer name to calibrate.

M. Sensor type being calibrated.

N. Serial numbers of the instrument and the sensor being calibrated.

O. Requested range for customer calibration.

P. Method and equipment used to calibrate the thermometer.

Q. Temperature or humidity used to test the thermometer.

A. If the instrument readings and the test temperatures are different, the thermometer may be recalibrated if possible and if necessary. The readings in this example are the same, so no action is needed.

S. Even with the most expensive equipment and controlled environments, measurements cannot always be 100% accurate. The uncertainty of doubt accounts for this possibility. If the measurement uncertainty is ± 0,04 °C, the test results can be senior or lower of 0,04 °C at the temperatures indicated in the certificate. The resolution of the instrument must also be added to this. Thus, if the measurement uncertainty is ± 0,04 °C and that the resolution of the instrument is 0,01, total uncertainty of measurement would be ±0,05 °C.

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