U.S. Metric Association (www.metric.org)

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The U.S. Metric Association (USMA), Inc., is a national non-profit organization that was founded in 1916. It advocates U.S. conversion to the International System of Units, known by the abbreviation SI (ess-eye) and also called the modern metric system. The process of changing measurement units to the metric system is called metric transition or metrication.

Among other things, this site contains information about the metric system, with some specifically designed for educators, as well as information about USMA and links to some other sites.

Conversions between unit systems are a poor way to learn the metric system, and conversion factors (or numbers converted with inappropriately-high precision) can make the metric system look complicated. Therefore we do not supply unit conversion utilities, but Google has a calculator that understands units.

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What's New: Updated Information by Date: 2010-07-24: The Fair Packaging and Labeling Act page in our laws section now includes information about NIST's proposal to amend the law to make inch/pound units optional, thus allowing metric-only labels as well as dual units. 2010-07-01: Added a reprint of a Metric Today article about metrication at Proctor & Gamble to the Going Metric Pays Off page. 2010-06-17: PDF of the 2010-July/August issue of Metric Today is now available online for USMA members. 2010-06-02: Added a reprint of a Metric Commission Canada's Metric Monitor article about industrial chemicals to the Going Metric Pays Off page. 2010-04-15: PDF of the 2010-May/June issue of Metric Today is now available online for USMA members. 2010-04-15: Check out the revised the Metric Today page, including a short history of USMA's newsletter. 2010-03-18: Added an Imperial Express SuperChair metric elevation sign, courtesy of Marc Sayce, to the metric signs page. 2010-03-12: Added a reprint of a Metric Today article about Ingersoll-Rand to the Going Metric Pays Off page. 2010-02-28: See the notice about NCWM's Weights and Measures Week, 1 - 7 March 2010. 2010-02-11: Added a publication (NIST Special Publication 1038: The International System of Units (SI) — Conversion Factors for General Use) to the SI reference publications page.

To be found in the 2010 July/August issue of Metric Today: What did the creator of the Dewey Decimal System think about metrication? How are IEEE standards' unit usage reviewed? What's the smallest force ever measured? What's new in Australian measurement? How do federal agencies participate in standardization? (PDF of the 2010 July/August issue available now for USMA members. Contact the USMA Webmaster for access.) Metric Today is a membership benefit of joining USMA

Now Available: The Metric System Poster Lend a hand to your local school. Help spread the metric message by gifting it with this colorful poster! Sized 53 cm × 71 cm and printed on thick glossy paper in full color, this poster displays the International System of Units. For U.S. destinations, the poster is $10, including shipping in a mailing tube (add $7 for each additional poster). [For non-U.S. orders, e-mail valerie.antoine@verizon.net to obtain cost of shipping/handling.] Visit USMA's supplies page to order.

FREE: SI Metric Units Poster A SI Metric Units Poster is available from USMA for the shipping/handling fee of $1.50 Titled SI Units, the poster contains the seven SI base units and most of the SI derived units with special names. Printed in two colors, black and red, the poster looks very similar to the adjacent illustration. Suitable for mounting on a wall, this 28 cm by 43 cm poster was developed to accompany a set of materials sent to schools in the Montgomery County (Washington DC) area. A large supply of these posters remain, and USMA will send them free for the cost of shipping and handling. To order, send $1.50 each for shipping/handling with a request for the free SI Units chart to: USMA, 10245 Andasol Avenue, Northridge CA 91325-1504. For multiple copies of the poster, e-mail valerie.antoine@verizon.net for the cost of shipping and handling.

Now Available: Think Metric Mugs This 250 mL mug is dark blue with gold printing showing names and symbols of common SI units, and is available for $15 each (including shipping and handling) while supplies last. To order, send your name and address and $15 per mug to USMA, 10245 Andasol Avenue, Northridge CA 91325-1504.

Information about USMA:

• USMA and its services:
  • USMA mission and activities (Why we exist, and what we do)
  • A brief history of the U.S. Metric Association (1916 to the 2000s)
  • USMA's Certified Metrication Specialist (CMS) program (How to become qualified)
  • USMA's Science Fair awards program (Become a judge, use your metric talents)
  • USMA's E-mail Listserver (Mailing List) (Join the metric discussion. You can subscribe free.)
  • USMA member-only information (Must be a current dues-paying member to access this information. USMA members may receive the username and password (changed yearly) by contacting the USMA Webmaster.)
• Publications and supplies:
  • Metric Today, the USMA newsletter (USMA's bi-monthly publication)
  • Metric supplies and training aids (Available from USMA: style/usage guides, rulers, thermometers, measuring tapes, posters, diagrams, bumper stickers, and booklets) [PDF version: supplies-list.pdf]
    • Guide to the Use of the Metric System (Our primary metric publication)
    • Metric Bibliography and Metric Today Archive (Metric information available for research purposes)
  • Metrication resources for businesses (Help for business/government members converting to metric)
  • Metric posters (Here's what's available from USMA)
  • Free metric fliers (Free for downloading, or for the cost of a SASE)
  • USMA's educational materials (See below, or click on this link)
• Membership:
  • USMA membership application (How to join us, how to help the cause) [PDF version: membership.pdf]
  • USMA officers (USMA's organizational leaders)
  • USMA Chapter guidelines (How to organize a local USMA Chapter)
  • Canadian Metric Association (CMA) (Our sister organization to the north)

Metric System Information:

• Why use the metric system:
  • FAQ: Frequently Asked Questions (Answers to miscellaneous questions about the metric system)
  • Decimal nature of the metric system (Why decimal is better)
  • How going metric pays off (Stories of successful transition to metric)
  • Unit mixups (Incidents, and in some cases costly disasters, that involved confusion between units or systems of measurement)
• Using the metric system:
  • Commonly used metric system units, symbols, and prefixes (The basics of the metric system)
  • Detailed list of units, symbols, and prefixes, plus SI unit diagrams (Charts showing relationships)
  • SI prefixes and their etymologies (Origins of the prefix names)
  • SI unit definitions (Official definitions, both current and previous)
  • (Metric) numbers to remember (Common examples of metric usage)
  • Frames-of-reference for some metric units (Typical metric unit sizes)
  • Correct SI-metric usage (Including metric errors seen frequently)
  • Metric temperature scales (Degrees Celsius and kelvins)
  • Glossary of metric acronyms (initialisms, and abbreviations)
• Background and history:
  • Origin of the metric system (From its origins to becoming adopted by most of the world)
  • A chronology of the metric system (Important dates and associated documents in the history of the metric system)
  • Metric-system-related events and anniversaries (Some are observed each year)
  • Metric system laws and bills (Extensive law summaries provided courtesy of USMA member Gary Brown.)
  • Metrication in other countries (Advance of metric usage in the world, and how several other countries have changed to metric)
  • Logos used in various metric transitions (Take the quiz and learn about metric progress around the world.)
  • Decimal currency systems (Used throughout the world)
• For Your Information:
  • Reference publications: International System of Units (SI) (Important metric documents and standards: SI-metric usage guides, a few are free, some contain large tables of unit conversion factors.)
  • Published articles about metric (Years: 1996 to present)
  • Consumer products available in metric sizes (Examples of rational metric sizes/metric fills)
  • Popular and society/association magazines that use SI-metric (Some are 100% metric)
  • Metric system cartoons (Examples of metric humor)
  • Metric signs seen on roads in the U.S. (Some were installed in the 1970s, others are much newer)
  • International date and time notation (A standard format especially for all-numeric dates)
  • DYKT: Did You Know That ... (Items of continuing interest from USMA)
• Things You Can Do:
  • Things you can do to promote metrication in the U.S.
  • How to contact your legislators (Senate, House of Representatives, and White House)

Metric System Information for Teachers/Educators:

• Why teach the metric system (SI)? (Contributed by USMA member Dennis Brownridge)
• Using the metric system (SI) (A guide for teachers, students, and professionals provided by USMA member Dennis Brownridge.)
• National Metric Week (The history of, and quizzes and puzzles for use during this annual event and throughout the year.)
• Tips to educators for teaching the metric system, and ideas for schools celebrating National Metric Week (Ideas and lesson suggestions)
• Suggestion to teachers for a painless way to teach one facet of SI (Metric Patrol assignment sheets and work sheets are included to make it easier for teachers to implement this assignment.)
• Teaching metric to very young children (K-2)
• One school's experience in teaching math and science through Olympic Games competition
• Decimal nature of the metric system (Why decimal is better)
• Metric flashcards (PDF version): Basic and Advanced (Courtesy of USMA member Jim Elwell)

Available for Purchase the 17th edition (revised 2007) of USMA's Guide To The Use Of The Metric System A updated easy-to-use 34-page metric system style guide that shows the metric system units and symbols (short forms) and gives rules for using them. Appendixes contain information on technical units used in industry, conversion factors for the most commonly used units, and tips for remembering the everyday units and their sizes. This guide is also a very useful reference for teachers. Click here for a Table of Contents. 1 to 9 copies: $15 each, plus $4.00 shipping/handling for single copy 10 or more copies: $12.00 each For multiple copies, e-mail valerie.antoine@verizon.net for the cost of shipping and handling. Visa and MasterCard accepted. Send orders to: USMA, 10245 Andasol Avenue, Northridge CA 91325-1504

NEED METRIC SUPPLIES? USMA offers a selection of books, charts, posters, rulers, measuring tapes, bumper stickers, and thermometers specifically for learning the metric system. These and more items can be found on USMA's metric supplies and training aids page.

Other Metric System Information and Related Standards links

Click on these external links for non-USMA metric Web sites with important and useful information.

• Links to Other Metric System Information, Standards, Guides, and Policies
  • Unit conversion utility/calculator
  • Metric system laws (See also the Metric system laws and bills provided by USMA)
  • Federal government
  • State and local government
  • Educational organizations
  • Other professional organizations
  • International
  • USMA members
  • Standards links

Your comments, suggestions, and questions are welcome. E-mail: USMA Webmaster