considerations for in-house calibration

Regular calibration is critical to quality manufacturing operations. Instruments need to be calibrated over time to ensure accuracy. An organization can do this by using a third party calibration laboratory or conducting in-house calibration. At first thought, it might seem easier to calibrate on your own. Before choosing, there are 3 considerations for in-house calibration to think through.

Meeting Quality Guidelines

Organizations must conduct calibration testing that meets documented calibration requirements. An internal QMS (quality management system) may contain requirements stipulating testing frequency and laboratory proficiency. Regulatory or accrediting bodies, such as ISO 9001 or AS 9100, have multiple quality management requirements. A manufacturer must consider if it is possible to meet all requirements when performing in-house calibration.


A common misconception is that in-house calibration saves time. When shipping to a third party lab, it does take time for items to be transported and undergo testing. Compare that to performing calibration in-house. In most cases, it will take an in-house technician longer to test the same items. An in-house technician is not required to perform testing on the same types of instruments continually versus a third party calibration lab technician. Oftentimes the person performing in-house calibration testing has other responsibilities, which may be put on hold while testing occurs. This effect is most common in small to midsize manufacturing environments. Another option is onsite calibration services. During onsite calibration, third party calibration technicians perform testing at your location. This option takes the absolute least amount of time on regards to total testing time and out of service equipment.


One of the main considerations for in-house calibration testing is the initial investment. Standards require a considerable upfront expense. Third party calibration laboratories have an easier time recouping the cost, due to the volume of tooling that is tested with each standard. Anyone that is part of the in-house calibration team will need ongoing, formal training on calibration procedures. The in-house calibration team may need to be staffed with new hires, or existing employees that will take on extra work or switch roles. An area must be established for calibration testing. This may require building a new work space. A testing area must have controlled temperature and humidity.

ISO 17025 Accreditation

ISO/IEC 17025 accreditation is given to laboratories that meet calibration testing competency requirements. Many quality guidelines require that calibration should be performed by an ISO 17025 accredited laboratory. As one of the main considerations for in-house calibration, this can be problematic. The accreditation process requires yearly expenses, and the laboratory must pass thorough audits and reviews. If you are required to have calibration testing performed by an ISO/IEC 17025 accredited laboratory, in-house calibration will most likely not work for your quality program.

Keep these considerations for in-house calibration in mind as you make your decision.