About metrology

Metrology is a science on measurements.

Metrology covers the domains of units of measurement and their measurement standards, measuring instruments and their scope, as well as all theoretical and practical issues referring to measurements.

Metrology is divided into three major fields: legal metrology, scientific metrology and industrial metrology.


Legal metrology is a branch of metrology regulated by the law and other regulations with the purpose of establishing confidence in the results of measurements within the scope of legal measurements. It refers to the activities arising from regulatory requirements and concerning measurements, units of measurement, measuring instruments and measurement methods implemented by the competent bodies.


Scientific metrology is a branch of metrology dealing with the matters common for all metrological issues regardless of the measured quantity. It encompasses general theoretical and practical problems regarding units of measurement, including their realization and their dissemination by means of scientific methods, problems of measurement errors and uncertainties as well as problems of metrological properties of measuring instruments.


Industrial metrology deals with measurements in production and quality management. It comprises calibration procedures, calibration periods, measurement process management and management of measuring instruments in industry with the purpose of assurance of their conformity with the requirements for their intended use.

The importance of metrology today is the consequence of the globalization of trade and of the need for elimination of technical barriers to trade.

It is therefore necessary to harmonize national legislations and conformity assessments as well as verification procedures.


National metrology acts usually regulate the following fields:

  • Legal units of measurement
    (in the majority of countries it refers to the SI units)
  • Physical realizations of legal units of measurement
    (measurement standards: prototype or laboratory realizations of basic units)
  • Hierarchy of measurement standards – their maintenance and keeping
    (harmonization with international measurement standards of higher accuracy and calibration of secondary measurement standards and working measurement standards, which assures traceability of measurements)
  • Technical regulations on measuring instruments cover metrological, technical and administrative requirements (for the fields of public interest such as trade, air protection, environmental protection, traffic surveillance and safety at work)
  • Metrological surveillance over measuring instruments
    (type approval of measuring instruments; initial verification; subsequent verification; surveillance over the use of measuring instruments)
  • Metrological surveillance over prepacked consumer goods
    (requirements for unambiguous marking, standardization of package size, metrological surveillance and prevention of misleading packaging)

  • Production management, import, repairs and sale of measuring instruments

  • Structure and organization for legal metrology, i.e. assurance of metrological infrastructure
    (scientific body as a national metrological institution; central body for harmonization and calibration; local bodies for law implementation).

The international collaboration and harmonization of measures, procedures and metrological requirements are of particular significance for today’s metrology.