The unit under calibration or the unit under test – the instrument being calibrated.

Transfer measurement

A transfer measurement is a type of method that enables making a measurement to a higher level of resolution than normally possible with the available equipment.

Test accuracy ratio (TAR)

In a calibration procedure, the test accuracy ratio (TAR) is the ratio of the accuracy tolerance of the unit under calibration to the accuracy tolerance of the calibration standard used.

Standard (measurement)

A standard (measurement standard, laboratory standard, calibration standard, reference standard; an étalon) is a system, instrument, artifact, device, or material that is used as a defined basis for making quantitative measurements. 


Self-calibration is a process performed by a user for the purpose of making an IM&TE instrument or system ready for use.

Performance Test

A performance test (or performance verification) is the activity of verifying the performance of an item of measuring and test equipment to provide assurance that the instrument is capable of making correct measurements when it is properly used. 

On-site operations

Operations that are based in or directly supported by an established calibration laboratory facility, but actually perform the calibration actions at customer locations.

Mobile operations

Operations that are independent of an established calibration laboratory facility. Mobile operations may include work from an office space, home, vehicle, or the use of a virtual office.


A set of operations performed for the purpose of determining the value of a quantity

Interlaboratory comparison

Organization, performance, and evaluation of tests or calibrations on the same or similar items or materials by two or more laboratories in accordance with predetermined conditions.

How can we help?