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U.S. Metric Association

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The US Metric Association (USMA), Inc., is a national non-profit organization that was founded in 1916. USMA advocates completing the US conversion to the International System of Units, known by the abbreviation SI (ess-eye) and also called the 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 other selected metric sites.

What's New: Updated Information by Date:

2014-12-20: PDF of the 2015-January/February issue of Metric Today is now available online for USMA members.

2014-11-18: Please note USMA's new address.

2014-11-08: PDF of the 2014-November/December issue of Metric Today is now available online for USMA members.

2014-08-20: PDF of the 2014-September/October issue of Metric Today is now available online for USMA members.

Effective immediately: USMA's mailing address is:

U.S. Metric Association, Inc.
P.O. Box 471
Windsor CO 80550-0471

Correspondence already sent to USMA's previous address will be forwarded as necessary.

If you live in New York State:

New York State is the only US jurisdiction that has not yet adopted the 1999 amendment to the Uniform Packaging and Labeling Regulation (UPLR) that permits the option of eliminating non-metric units from labels of products not regulated by the federal Fair Packaging and Labeling Act (FPLA). Please contact USMA's PR Director if you are willing to help with this cause.

Is Your Company or Organization Going Metric?
We'd Like to Know

Perhaps your hospital is changing over to measuring patients' height and weight in metric units only, or your company's product line is going hard metric. We'd be very interested in the how and the why. And, with your permission, we'll tell your story in our newsletter, Metric Today. Please contact USMA.

To be found in the 2015 January/February issue of Metric Today:
  • How was the metric system introduced in Turkey?
  • What does the British Prime Minister think of metric units?
  • Why is it hard to determine the value of G?
  • How is the new definition of the kilogram coming?
  • Why is it tricky to sell honey in metric units?
(PDFs of the last three issues are available for USMA members. Contact the USMA Webmaster for access.)

Metric Today is a membership benefit of joining USMA

Metric Today - latest

250 mm ruler
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.
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 US addresses. For non-US orders, contact USMA 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 US destinations, the poster is $10, including shipping in a mailing tube (add $7 for each additional poster). [For non-US orders, contact USMA to obtain cost of shipping/handling.] Visit USMA's supplies page to order.

The Metric System poster

SI Units chart
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.

For multiple copies of the poster, contact USMA 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.

Think Metric mug

Information about USMA:

Metric System Information:

Metric System Information for Teachers/Educators:


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 for the cost of shipping and handling. Visa, MasterCard, and Discover accepted. Send orders to USMA.


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

tape and thermometer

Links to Other Selected (Non-USMA) Metric System Information, Standards, Guides, and Policies

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Your comments, suggestions, and questions are welcome.
Contact USMA
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Web site maintained by the USMA Webmaster.
Updated: 2015-01-01