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SI Education & Training

The International System of Units (SI), commonly known as the metric system, is the international standard for measurement. SI use in product design, manufacturing, marketing, and labeling is essential for United States industry's success in the global marketplace. SI measurement system familiarity and fluency must be developed along the Science, Technology, Engineering, Art, and Mathematics (STEAM) career pipeline to produce an U.S. engineering workforce with this essential 21st century skill.

Metric Program Training

Looking for opportunities to expand your International System of Units (SI) subject-matter knowledge and skills? Ongoing opportunities throughout the year are available to fit your schedule. Explore technical training and professional development opportunities offered by the NIST Metric Program.


Teaching the New SI

In November 2018, the world’s measurement experts voted and unanimously approved a revision of the SI that establishes a measurement system entirely based on physical constants of nature. The changes took effect on World Metrology Day, May 20, 2019. Learn more about the Road to the Revised SI.

The Measurement League: Guardians of the SI


Graphic of League of SI Superheroes

The Measurement League: Guardians of the SI are superheroes dedicated to the fight against uncertainty, imprecision, and inaccuracy and to improving the quality of our lives and the things we build, using their incredible powers of measurement to perform amazing feats of science and engineering. This comic book-style video animation series has been developed to help middle school students learn about the 7 SI base measurement units. Videos are available on the NIST YouTube Channel.

Episode 1: Desperate Measures!
The SI Superheroes use the power of measurement to help a stranded soccer player get home.

Episode 2: Running Out of Time!
The SI Superheroes battle archvillain Major Uncertainty in a race to keep the world's satellite navigation system "on time."

Episode 3: Mass Hysteria!
The nefarious Major Uncertainty has kidnapped Monsieur Kilogram, putting the world’s measurements of mass in jeopardy.

Episode 4: Two Truths & a Lie.
After rescuing Monsieur Kilogram and capturing Major Uncertainty, our Superheroes take a break and play a game of "Two Truths & a Lie."

Companion Resources

  • Meet the Measurement League – Learn more about each SI Superhero
  • SI Superhero Card Set (PDF) - Printable cards in this set list each superhero’s name, picture, symbol, and the measurement unit represented. A short description of the superhero’s powers are on the back of each card.
  • Coloring Pages (PDFs) - Printable coloring sheets, ideal for young students.
  • Valentine’s Day Cards (PDFs)
  • SI Measurement System Chart - SP 304A (2017) - This publication is a colorful chart explaining the 7 base units of the SI, prefix symbols, and features the Measurement League: Guardians of the SI. Submit hard copy requests to TheSI [at] or print a copy (select “print to fit”). Original dimensions: 279 mm by 432 mm (11 in by 17 in).


Created May 11, 2016, Updated June 1, 2021