What is calibration?

Your measurements are wrong!

Measurements are only as reliable as the tools and instruments behind them. Without calibration, even the best equipment can drift over time and deliver inaccurate results. The consequence may be poor quality, production errors, or failure to meet customer and industry requirements.

By calibrating your instruments regularly, you ensure that every reading reflects reality. This provides confidence in your results and supports compliance with international standards. Calibration is not just a technical necessity – it is a cornerstone of reliable quality management.

What is calibration?

In metrology, calibration is the comparison between the measurement values delivered by your instrument and those of a calibration standard with known accuracy. Such a standard could be a reference device with verified accuracy.

The calibration service may include adjustments to meet acceptance criteria, but strictly speaking, the term calibration refers only to the act of comparison and does not include adjustment.

Traceable calibration

Today, there are two types of calibration: traceable and accredited.

A traceable calibration means that the calibration laboratory compares the measuring instrument with a known reference standard, i.e. a traceable standard. The standard is a quantity based on the seven SI base units together with a number of derived units. (SI stands for the International System of Units.)

The seven SI base units are precisely defined by seven natural constants. A large number of derived units are then built upon these. Previously there was also a group called supplementary units, but they are now included among the derived units.

• Meter (m)
• Kilogram (kg)
• Second (s)
• Ampere (A)
• Kelvin (K)
• Mole (mol)
• Candela (cd)

In other words, a traceable calibration is only a comparison with a known reference and should not be confused with accredited calibration.

Calibration certificate

After calibration, a calibration certificate is issued. A calibration certificate should not be confused with a calibration statement (see below), which is issued only after an accredited calibration.

Accredited calibration

For calibration to be accredited, the laboratory performing the calibration must be accredited by an independent accreditation body. An accredited laboratory must meet international criteria regarding its quality system and technical competence. There is full traceability throughout the chain up to the international organizations that oversee the local accreditation bodies. These international organizations set stricter requirements for measurement uncertainty and require accredited laboratories to regularly send reference instruments for calibration.

The accreditation is awarded within a specific measurement field, the “scope of accreditation,” in accordance with the international standard ISO/IEC 17025. Element Metech offers accredited services in a wide range of areas. For a complete list of our scope, visit Swedac.com.

Calibration statement

After an accredited calibration, a calibration statement is issued. Please note that a calibration statement should not be confused with a calibration certificate.

Verification

A type-approved weighing system must meet established requirements that demonstrate its performance. Verification (also known as legal verification) is the process of checking that the scale complies with these requirements. Verification is performed according to an accredited method, which means that the laboratory conducting the test must be an accredited inspection body.

When the scale has been tested and meets the requirements, a verification certificate is issued, showing that the requirements are fulfilled. Note that verification is time-limited, and we recommend that all measuring instruments requiring regular calibration are included in a service agreement.

Adjustment

Adjustment simply means tuning a measuring instrument so that its results agree with a given reference. If calibration results in a deviation, an adjustment can be made. Note that once an adjustment has been performed, a new calibration is required.

Self-check

A self-check of an instrument is exactly what it sounds like: a control performed by the user to continuously ensure that the instrument measures correctly. A self-check is often used as a complement to accredited calibration and follows strictly defined routines.

Calibration laboratories

Measuring instruments must be reliable and should therefore be calibrated. Decisions made on incorrect grounds can lead to design errors and faulty results. To ensure reliability, instruments should be calibrated regularly in a calibration laboratory. Visit Swedac for a complete list of Element Metech’s laboratories.

Calibration points

As the customer, you are responsible for selecting calibration points before the calibration. The calibration points checked will always be listed on the certificate or statement issued in connection with the calibration.

Why calibrate?

So why should you calibrate and how often is appropriate? Read more about it HERE.