Tompkinsville, KY 42167

Calibration, Verification, and Validation

Calibration, Verification, and Validation

During the process of creating our quality management system conforming to the ISO 9001:2015 standard, we’ve discovered the importance of distinguishing between calibration, verification, and validation.


Calibration is when equipment is compared to an established standard and can be altered. If the equipment does not match the standard and can be adjusted to meet the standard, the process is considered calibration. There are numerous calibration labs that specialize in making sure equipment performs correctly.


Like calibration, the verification process also involves comparing equipment to a standard. In verification, equipment is checked against a calibrated piece of equipment. The measurements on a verified piece of equipment cannot be altered. When verified equipment is out of calibration, it usually makes the most sense to discard it and replace it with a new one.

For example, tape measures are considered verified equipment. The standard we use to check the tape measures is a calibrated ruler. This ruler must be sent off for re-calibration every three years to ensure the markings on it are still correct. When the measurement marks on a tape measure don’t match up with the marks on the calibrated ruler within the allowed tolerances, the tape measure must be thrown away and replaced with one that does match the calibrated ruler.


Validation differs from calibration and verification in that it does not involve a reference standard. Validation provides assurance that the equipment being tested produces consistent results within the acceptable tolerances. A way to validate equipment that cannot be calibrated or verified is to run a few identical parts through the machine and evaluate them to see if the end results are the same. For example, you would check to see if nails were nailed in the same places on each item, if holes were drilled the same distance apart on each item, etc. as applicable to the machine being tested.

Each type of equipment has different recommended intervals for how often it needs to be calibrated. If you don’t know how often your equipment needs to be calibrated, verified, or validated, a good place to start is to ask for the manufacturer’s recommendation.