Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

5628 Balance and Scale Calibration and Uncertainties - IAAO Participants Only - CANCELLED

NIST is closely monitoring guidance from Federal, State, and local health authorities on the outbreak of COVID-19. To protect the health and safety of NIST employees and the American public they continue to serve, NIST has decided to cancel Balance and Scale Calibration and Uncertainties seminar. For more information on COVID-19, please visit:


This 4-day seminar will cover the calibration and use of analytical weighing instruments (balances and laboratory/bench-top scales), including sources of weighing errors in analytical environments, methodologies for quantifying the errors, and computation of balance calibration uncertainty and global (user) uncertainty. Attention will be given to error sources, selection of reference standards, and various calibration  procedures used in the weighing industry.  Approximately 50 percent of the time will be spent doing hands-on exercises, calibrating a variety of balances, accumulating data, and developing uncertainty budgets.  The focus will then move to the use of balances in an analytical environment and regulatory environment where compliance with pharmaceutical (FDA/ USP) and international requirements will be discussed and practiced.  Methodologies for process measurement assurance techniques in analytical weighing will also be covered.  Participants will leave with a working skill-set of balance calibration methods, uncertainty estimation, measurement assurance concepts & minimum sample quantity computations that can be applied directly to their calibration and/or use of weighing instruments. This NIST Seminar is designed for beginner to advanced users of balances, metrologists, ISO/IEC 17025 assessors and accreditation bodies, or calibration managers wanting a better understanding of balances and associated uncertainties in organizations where analytical weighing is an integral part of operations. This seminar is limited to 12 participants.  All participants will receive a USB stick with a comprehensive collection of national and international references and documents.

Learning Objectives:

At the end of this seminar, using your references and notes, you will be able to:

  • SUMMARIZE the principles and concepts of Measurement Traceability, Measurement Assurance, and Measurement Uncertainty.
  • EXPLAIN the interrelationships between traceability, measurement assurance, and measurement uncertainty.
  • SELECT the appropriate reference standards for the calibration of weighing instruments.
  • SELECT the appropriate international or national method/procedure for the calibration and/or use of weighing instruments in the ISO/IEC 17025 or regulatory environment.
  • DESCRIBE the NIST Eight-Step Process of Measurement Uncertainty Estimation applied to weighing instrument calibration and/or use
  • CONSTRUCT a procedure or outline for a balance calibration.
  • BRAINSTORM, CATEGORIZE, and QUANTIFY potential error sources and uncertainty contributors to weighing devices.
  • DEVELOP a basic uncertainty budget for weighing devices that is validated with the principles of measurement assurance.
  • ESTIMATE the minimum sample quantity for weighing instruments.

Materials & Supplies:

All materials and supplies provided by seminar hosts.


  • Read Euramet cg-18 before the seminar.  After reading Euramet cg-18, it will become obvious that knowledge of basic and some advanced mathematics skills are needed to be successful in the Balance Calibration and Uncertainty Seminar.  It is also recommended that you complete the Recommended Math Exercises to enhance your participation in the seminar. These topics will be covered during the seminar; however, early review will increase your understanding of the concepts. RECOMMENDED MATH EXERCISES
  • Submit completed mathematics exercises for which you want feedback to isabel.chavez [at] (isabel[dot]chavez[at]nist[dot]gov). The provided feedback will let you know which topic areas need some review. REQUIRED BALANCE MATH EXERCISES

Below is a list of video resource's that will be helpful should you need review of the mathematics skills prior to the Balance Calibration & Uncertainty Seminar:


Complete and submit the ‘Required To Know’ math exercises that contain evidence of mathematical skills you must have to be successful in the seminar: There is no planned review of these basic mathematics topics during the seminar.

Pre-Work Deadline:

Submit to instructor by June 1, 2020.

Minimum Requirement(s):

Successful completion requires that participants fully participate in all classroom and laboratory exercises, turn in or present accurate work assignments, and be present for the entire course, in addition to successfully completing the Balance Calibration Mathematical Exercises.
*Homework note: students generally report taking one to two hours for homework each night.


National Metrology Institute personnel within the Interamerican Metrology System (SIM), beginner to advanced users of balances or calibration managers wanting a better understanding of balances and associated uncertainties in organizations where analytical weighing is an integral part of operations.


This class is for SIM participants only and payment arrangements are made through the International and Academic Affairs Office.  Please contact Andrew Conn at andrew.conn [at] (andrew[dot]conn[at]nist[dot]gov) for further information.        


Isabel Chavez, Micheal Hicks, and Mark Ruefenacht
Office of Weights and Measures
Phone: (301) 975 - 2128
Email: isabel.chavez [at] (isabel[dot]chavez[at]nist[dot]gov)

Technology Requirement(s):

Participants must be able to open, use and save MS Excel workbooks from a NIST OWM provided USB memory stick during the seminar. Availability of a scientific calculator is encouraged.



NIST / Office of Weights and Measures

You will need a government-issued photo ID (e.g., passport or driver's license) when you check into the Visitors Center at the entrance of NIST on Monday morning.  If you will be driving, please bring your Vehicle Registration card also.

PLEASE NOTE: Effective July 21, 2014, under the REAL ID Act of 2005, agencies, including NIST, can only accept a state-issued driver's license or identification card for access to federal facilities if issued by states that are REAL ID compliant or have an extension. NIST currently accepts other forms of federally issued identification in lieu of a state-issued driver's license, such as a valid passport, passport card, DOD's Common Access Card (CAC), Veterans ID, Federal Agency HSPD-12 IDs, Military Dependents ID, Transportation Workers Identification Credential (TWIC), and TSA Trusted Traveler ID. See Visitor Information for the latest information.


Created January 21, 2020, Updated March 25, 2020