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.

We don't supply unit conversion utilities, but Google has a calculator that understands units.

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What's New: Updated Information by Date: 2012-05-01: USMA's mailing address has changed. Here's our new mailing address. 2012-04-30: Added photos of two signs to the California section of the metric road signs pages. 2012-04-20: PDF of the 2012-May/June issue of Metric Today is now available online for USMA members. 2012-03-21: See the notice about World Metrology Day, 20 May 2012. 2012-03-09: Added the question, "What about atmospheric pressure: hectopascals, kilopascals?" to the FAQ. 2012-02-29: Added some new acronyms to the glossary of metric acronyms. 2012-02-23: PDF of the 2012-March/April issue of Metric Today is now available online for USMA members. 2012-02-15: Added a photo to the snacks section of the products in metric sizes pages. 2012-02-05: Added a yogurt section to the products in metric sizes pages. 2012-02-05: Added two reprints of Metric Today articles about metrication in the United Arab Emirates to the new relatively Recent international metric advances page. 2012-02-05: Added two signs to the New York section of the metric road signs pages. 2011-12-20: PDF of the 2012-January/February issue of Metric Today is now available online for USMA members.

World Metrology Day 20 May 2012 See the following BIPM link for information: World Metrology Day 2012 See also USMA's list of Metric events and anniversaries.

To be found in the 2012 May/June issue of Metric Today: Why was there a North American Watt Balance Absolute Gravity Comparison? How can you participate in World Standards Week...? When is World Metrology Day? What happened on Sunday Morning, metrically speaking? Why are Danish rulers a good way to have fun in a carpentry shop? What's Myanmar planning in the world of weights and measures? (PDF of the 2012 May/June issue available now for USMA members. Contact the USMA Webmaster for access.) Metric Today is a membership benefit of joining USMA

Now Available: 250 mm rulers This plastic ruler, manufactured for QSI Corporation, is available free to USMA members—or $1 for non-members—while the supply lasts. In addition to the ruler scale, the front side contains SI prefixes. The back side contains lists of SI units, conversions, and constants. To get one, send your name and address (plus $1, if you're not a USMA member) to USMA Headquarters. No e-mails or phone calls, please. Want more than one? Just add $1 for each additional ruler, or quantity discounts are as follows: package of 5 for $3.50 (70 cents each) package of 10 for $5.00 (50 cents each) package of 20 for $8.00 (40 cents each) package of 50 for $12.50 (25 cents each) package of 100 for 20.00 (20 cents each) All prices include shipping/handling to U.S. addresses. For non-U.S. orders, contact USMA Headquarters for the cost of shipping and handling.

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, contact USMA Headquarters 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 Headquarters. For multiple copies of the poster, contact USMA Headquarters 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 Headquarters.

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)
  • 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)
  • 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)
  • Recent international metric advances (What is changing metrically outside of the U.S.)
  • 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 the metric system, metrication, and related standards
  • Consumer products available in metric sizes (Examples of rational metric sizes/metric fills)
  • Metric signs seen on roads in the U.S. (Some were installed in the 1970s, others are much newer)
  • Our world in (metric) numbers
  • Metric system cartoons (Examples of metric humor)
  • International date and time notation (A standard format especially for all-numeric dates)
  • Popular and society/association magazines that use SI-metric (Some are 100% metric)
  • 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 (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, contact USMA Headquarters for the cost of shipping and handling. Visa, MasterCard, and Discover accepted. Send orders to USMA Headquarters.

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 (Non-USMA) Metric System Information, Standards, Guides, and Policies

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