What's the Difference Between NIST Traceable and ISO Calibration Certificates?
Mar 28th 2025
Calibrating instruments, including scales and balances, are a key aspect of maintaining precision, accuracy and quality. Documentation is a major component of quality systems, which is why calibration services include a traceable calibration report. One question we are often asked is "What is the difference between a NIST traceable and ISO calibration report?". To answer this, we will define each and how it is relevant to your particular processes.
NIST Traceable Calibration Certificate
NIST-traceable calibration certificates confirm that a device's calibration is traceable to the National Institute of Standards and Technology (NIST) standards, ensuring accurate measurements and a documented chain of measurement leading back to NIST. In simpler terms, this means that the calibration weights used to calibrate the device are documented and confirmed against the standards set forth by NIST.
What is Included on a NIST Traceable Certificate?
- Name and details of the device
- Certificate identification code
- Name of the lab that conducted the calibration
- Results of the calibration
- Evidence of traceability
How does this benefit you?
- Helps ensure the accuracy and reliability of measurements
- Improved quality and a reduction of errors
- Improvements in efficiency
- Trust in the documented results found in the calibration certificate
- Adherence to internal and regulatory quality guidelines
Learn even more about NIST-traceable calibrations.
ISO Calibration Certificate
The International Organization for Standardization (ISO) is a quality system standard with requirements for certain procedures, documentation and system management. An ISO accredited lab is periodically audited by an accreditation body to ensure that their procedures, documentation and system management are up to date and in compliance with the ISO standard requirements. Most importantly they will audit actual calibration procedures in each specific calibration field that the lab is accredited for to make sure calibration technicians are competent in that specific field of calibration.
What's Included on an ISO Certificate?
- Name and details of the device
- Certificate identification code
- Name of the lab that conducted the calibration
- Environmental conditions in the location and at the time of the calibration
- Results of the calibration
- Evidence of traceability
- An estimation of the calibration uncertainty
- Accreditation mark and lab's accredited certificate number
Benefits of ISO Accredited Certificates
- Ensures compliance with process, documentation and management of calibration services
- Demonstrates a high-level of expertise and professionalism of the calibration provider
- Trust in knowing your calibration meets the highest standard of quality
- Required by most organizations that are also ISO accredited
Summary
An ISO certificate is always NIST-traceable, but not every traceable certificate is ISO accredited. NIST-traceable calibration certificates document the traceability of the test standards to a defined standard through an unbroken chain of comparisons. ISO accredited certificates confirm that the calibration was performed by an accredited organization that meets the guidelines set forth by ISO. The difference between them is that one validates the test standards, while the other provides additional assurance that procedures, documentation and management meet quality guidelines that all ISO accredited organizations must abide by.
Now that you know what the differences are, you can make an informed decision about which certificate you need to maintain the standards of your own quality system and regulatory requirements.
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