Measurement Uncertainty Calculator Download

Integrity Solutions Group has prepared various analyses and presentations to establish an integrated means to assure technically correct, integrated, and cost-effective Measurement Uncertainty Estimates. A useful tool is a computerized calculation program that:

  1. helps reinforce knowledge of the subject,
  2. is rich in examples,
  3. is generally very faithful to the methodology,
  4. does not advocate the approach of one "Guru" over another "Guru",
  5. has been used by many,
  6. has had various improvements with time,
  7. remains current,
  8. is simple to validate,
  9. and, is free.

The only program known to meet this criteria is the "Uncertainty Calculator" by Chris Grachanen. This program can be downloaded from or or

Assessments at various labs indicate many Measurement Uncertainty problems (to the extent that some assessments were aborted) exist at the time of assessment. Organizations that have adopted this software and the integrated approaches of Integrity Solutions Group, available as described below, have been successful.


Available Integrity Solutions Group Reference and Guidance Documents

Experience worldwide has indicated that much confusion exists regarding Development Of Effective Measurement Uncertainty Estimates, Interface or Specification of Technical and Quality Requirements to Assure Competent Testing and Calibration, and proper interface with laboratories. This includes:

  • Lack of the understanding of the need for Uncertainty Estimates,
  • Lack of understanding of conditions when Uncertainty Estimates may not be necessary or appropriate,
  • Lack of clear guidance to determine when Uncertainty Estimates are applicable,
  • Lack of methods to cost-effectively provide such uncertainty estimates,
  • Lack of means to effectively assure reasonable interface between test and calibration laboratories,
  • Lack of necessary clarifying interpretation,
  • Lack of criteria to select appropriate tools for uncertainty,
  • Lack of clear evaluation of the recommended tools meeting reasonable criteria,
  • Lack of "hands-on" guidance,
  • Lack of clear guidance regarding specifications and review of submittals of requirements to and data from Test and Calibration sources.
  • Lack of means to simply review and accept lab produced data upon receipt,
  • Lack of understanding of terms and concepts relating to calibrations, verifications, characterizations, and testing that impacts on the approach to Uncertainty Estimates,
  • Lack of guidance for the Assessors relating to what is necessary and appropriate to understand in order to complete a viable assessment task to the requirements established by ISO/IEC 17025 and Accreditation Body Criteria.

Integrity Solutions Group has prepared various guidance and reference documents available on request to assist industry. Various versions of these documents are in worldwide use.

Please fill out our Information Request Form for any of the following documents:

  • Technical & Quality Specification to Assure Competent Calibration Services (Revision 8)
  • Calibration Acceptance Checklist (Revision 5)
  • Technical & Quality Specification to Assure Competent Test Services (Revision 2)
  • Test Acceptance Checklist (Revision 2)
  • Test Laboratory Position for Expression of Uncertainty and Confidence In Measurement (Revision 9)
  • Procedure for Expression of Uncertainty and Confidence In Measurement (Revision 3)

Integrity Solutions Group recommends that this web page be checked frequently as the data is frequently updated, especially those immediately above.


Available Reference and Guidance Documents for a Necessary Common Language

Definitions, terms, initialisms, acronyms as used in any industry are meant to serve two functions: 1) to explain the terms they define, and 2) to establish exact, consensus meanings of terms used throughout the industry. Unfortunately, the goal established is not always achieved in practice; therefore, the meaning or intent of terms should be stressed and provided to assure that communication between people and organizations does transfer the intended meaning of the terms used.

General definitions related to quality, especially for a Registered organization, are given in ISO 9001:2000, whereas ISO/IEC Guide 2 gives definitions specifically related to standardization, certification and laboratory accreditation. For Calibration Laboratories definitions given in the VIM (International vocabulary of basic and general terms in metrology, issued by BIPM, IEC, IFCC, ISO, IUPAC, IUPAP and OIML) should be used.

The ISO has provided additional information on the terminology in ISO/TC 176/SC 2/N526 Product Introduction Package: Module Guidance on the Terminology used in ISO 9001:2000 and ISO 9004:2000. This information can be downloaded from

Additional definitions and enhanced clarification of their intent within the area of Uncertainty Estimates, Testing, and Calibration is found in the Test Laboratory Position for Expression of Uncertainty and Confidence In Measurement (Revision 6) available by request by completing our Information Request Form .


Available Reference and Guidance Document to Demonstrate Software Adequacy

ISO/IEC 17025 clause (a) states that computers or automated equipment used for the acquisition, processing, recording, reporting, storage or retrieval of test or calibration data, necessitates that computer software be documented in sufficient detail and is suitably validated as being adequate for use. Similarly ISO 9001:2000 clause 7.6 necessitates software used in the monitoring and measurement of specified requirements be demonstrated to satisfy the intended application. Unfortunately, useful guidance to accomplish the demonstration of adequacy is not in the standards used most often in industry and for Accreditation or Registration.

Various very complex and often costly models for software verification and validation exist. Such models are indeed appropriate to complex processes such as nuclear safety system design, defense system and complex aerospace systems. Fortunately, a practical guidance document is available that considers the different software types available (commercial off the shelf or COTS or modified off the shelf or MOTS or CUSTOM software) in a manner that is reasonably achievable and can be successfully applied in laboratory, manufacturing, and related processes.

This guidance is found in a physically brief, but rather complete document, Software Validation in Accredited Laboratories A Practical Guide, by Greg Gogates of Fasor Technical Services, Inc. This information can be downloaded from