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 inappropriate 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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New or Updated Information by Date: 2008-07-03: A PDF of a Sizing Up the Situation metric estimation quiz has been added to the Metric Week page. 2008-07-02: Now available: USMA's new The Metric System poster on the metric system, designed specifically with schools in mind. 2008-06-30: An article from the Rochester NY Engineer has been added to the published articles about metric section. 2008-06-16: Added photos to the health foods et al page in the products in metric sizes section. 2008-06-04: PDF of 2008-July/August issue of Metric Today is now available online for USMA members. 2008-06-03: Added a second SI units diagram to the metric system units and metric posters pages. 2008-05-20: Updated the section of the laws pages, Interpretation of the International System of Units for the United States, to incude a 16 May 2008 Federal Register notice. 2008-04-27: Added an explanation of how to use the 1970's era GM metric unit converter. And here's how to get one, while the supply lasts. 2008-04-25: Added the tale of the escape of the 250-kilogram tortoise to the unit mixups page. 2008-04-14: Added a reprint of a Metric Reporter article about Anderton-Darby to the Going Metric Pays Off page. 2008-04-10: Added a reprint of a Metric Today article about Xerox to the Going Metric Pays Off page. 2008-04-09: PDF of 2008-May/June issue of Metric Today is now available online for USMA members. 2008-04-08: Now available—and free to USMA members—this 1970's-era GM metric unit converter, while the supply lasts. 2008-04-04: Updated the metric road signs section to add distance markers on the Eliza Furnace Trail in Pittsburgh PA, and distance markers on the Harriman Trail in Sun Valley ID. 2008-03-13: The greatly-revised Practical Guide to the International System of Units page, designed mainly for teachers and adults, is now available for learning the metric system. 2008-03-13: A PDF containing a PowerPoint-like slide presentation, for readers who wish to present the material to others has been added as a link to the Why teach the metric system (SI)? page. 2008-02-22: PDF of 2008-March/April issue of Metric Today is now available online for USMA members. 2008-02-08: Now available from USMA, "Think Metric" mugs, while the supply lasts. 2008-01-09: Added photos to the soft drinks and desserts categories of the products in metric sizes section. Also added a few brand names and sizes to some of the categories' lists.

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 USA destinations, the poster is $10, including shipping in a mailing tube (add $7 for each additional poster). [For non-USA orders, e-mail valerie.antoine@verizon.net to obtain cost of shipping/handling.] To order, print the order form and send it with your payment to USMA, 1130-G Arcadia Avenue, Arcadia CA 91007.

Now Available: Unit Converters This plastic circular metric unit converter, distributed by General Motors in the 1970s, is available free to USMA members—or $1 for non-members—while the supply lasts. To get one, send your name and address (plus $1, if you're not a USMA member) to USMA, 10245 Andasol Ave, Northridge CA 91325-1504. No e-mails or phone calls, please. Want more than one? Just add $1 for each additional converter. Need help using it? Here's how it works.

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.

To be found in the 2008 July/August issue of Metric Today: What units will the health care industry use for children's weights? Which industry announced a switch to metric units for its standards? What metric-related publications have recently been updated? Who's making metric music? How do you figure out where you are when you break down on a highway? Why is gravity different in math than in physics? (PDF version available now for USMA members. Contact the USMA Webmaster for access.) Metric Today is a membership benefit of joining USMA

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.

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
    • Metric Bibliography and Metric Today Archive (A set of two compact disks: the first CD contains a database of references to articles about metric from the mid 1940s to present, and indexes to various metric newsletters (including Metric Today); the second CD contains full-text PDFs of the entire Metric Today collection, as well as the entire Construction Metrication newsletter collection, along with indexes to help locate information in the PDFs.)
  • 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)
  • Our traditional units nightmare (Including conversion factors to SI)
  • 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 (Which countries are not metric, advance of metric usage in the world, and how several other countries have changed to metric)
  • Decimal currency systems (Used throughout the world)
• For Your Information:
  • Publications: International System of Units (SI) (Important metric references 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 conversion postage stamps (For stamp collectors)
  • 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.

• 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