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SI Measurement System Chart

Black and White graphic.  Left side has black images of scales, rulers, SI logo.  Right side has white images on black background of same items.  The middle of image has a gray cirle with EDUCATION in black letters.


Keywords: SI, metric system, base unit, kilogram, kelvin, meter, candela, second, ampere, mole, international
Audience: Students, Parents, Educators, General Public, Technology Coordinators, Outreach Ambassadors
Grade Level:  3 to Higher Education
Subjects: SI units, research at NIST: metrology


Colorful chart explaining the 7 base units of the SI (International System of Units) and prefix symbols, featuring the Measurement League: Guardians of the SI
Credit: NIST


This resource provides a colorful printable SI system chart, which displays the 7 SI base unit, prefix symbols, and features the Measurement League: Guardians of the SI superheroes, dedicated to the fight against uncertainty, imprecision, and inaccuracy and to improving the quality of our lives and the things we build. The superheroes include the following: Mole, Professor Second, Monsieur Kilogram, Ms. Ampere, Dr. Kelvin, Meter Man, and Candela. SI Prefix symbols featured in the chart are used to represent smaller or larger units by factors that are powers of 10. The chart provides an entertaining way to learn more about the International System of Units (SI). NOTE: Four new International System of Units (SI) prefixes (ronna, ronto, quetta, and quecto) were adopted in November 2022 and are not currently represented in this publication.

The chart may be printed on any paper size but is recommended to be at minimum 215.9 mm x 279.4 mm (8.5 in x 11 in).

Learning Objectives

  • Understand SI base units of measure
  • Learn metric prefixes
  • Recognize the definitions of base units


  • Required
    • Digital file
    • Paper
    • Printer
  • Recommended
    • 215.9 mm x 279.4 mm (8.5 in x 11 in) size paper


Use caution when handling paper edges to prevent injury.

Teaching Tips

Explain the SI base units, unit definitions, and metric prefixes. State each base unit depends upon a defining constant. Additionally, mention the combination of SI base units creates the SI derived units. Hardcopy charts are available while supplies last. Contact the NIST Metric Program at TheSI [at] (TheSI[at]nist[dot]gov) and include your name and U.S. mailing address.

Classroom Connections

Additional Resources


Created July 13, 2022, Updated January 16, 2024