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Metric Publications

As of August 16, 2023 the historic SI Units site has permanently retired. This page and complete Metric (SI) Program contains current SI information. Contact TheSI [at] (TheSI[at]nist[dot]gov) with comments, questions or concerns.

Federal Register Notice

Federal Register Notice
FR 28432-28433 (PDF)
Edition: May 16, 2008

Together NIST SP 330 and NIST SP 811 provide the legal interpretation of and guidelines for the use of the SI in the United States, as described in the Interpretation of the International System of Units (the Metric System of Measurement) for the United States.

SP 330 Cover

The International System of Units (SI)
Edition: 2019

This 2019 edition of NIST Special Publication (SP) 330 is the United States version of the English text of the ninth edition of the Bureau International des Poids et Mesures (BIPM) SI Brochure (the most current) published in 2019. The 2019 edition of NIST SP 330 replaces its immediate predecessor, the 2008 edition.

SP 811 Cover

Guide for the Use of International System of Units (SI)
Edition: 2008

This document gives the rules and style conventions for printing and using units, unit symbols and SI prefix symbols. The publication includes an editorial checklist for reviewing manuscripts' conformity with the SI and the basic principles of physical quantities and units. Appendix A provides the definitions of the SI base units. Appendix B gives conversion factors for converting values of quantities expressed in units that are mainly unacceptable to use with the SI to values expressed mainly in units of the SI. Appendix B also includes a simplified discussion of rounding numbers and rounding converted numerical values of quantities. This 2008 edition supersedes NIST Special Publication 811, 1995 Edition, April 1995.

NIST SP 1247

SI Base Units Relationships Poster
NIST SP 1247
Edition: 2020

This publication is a colorful poster illustrating the relationships of the International System of Units (SI) derived units with special names and symbols and the seven traditional base units.

SI Units Card Deck (SP 1297)
Credit: NIST

SI Units Card Deck
NIST SP 1297
Edition: 2023

This interactive educational activity offers a fun way for students to enhance their understanding of the International System of Units (SI), including the Defining Constants, Base Units, Derived Units with Special Names, and Prefixes. With multiple game variations, games may be differentiated for multiple instructional and skill levels.

NIST Metric Recipes Thumbprint SP1290
Credit: NIST

NIST Metric Recipes
NIST SP 1290
Edition: 2023

Cooking and baking using a kitchen scale is a fun way to build metric system abilities and apply measurement techniques. This recipe card series is ideal for both new and experienced chefs. Companion resources are available on the NIST Metric Kitchen.

Nist Special Publication 1038

The International System of Units (SI) - Conversion Factors for General Use
NIST SP 1038 (PDF)
Edition: 2006

This publication lists the units of the International System of Units (SI), or metric system, recommended for use in trade and commerce and other general uses by the National Institute of Standards and Technology. Much of the information in SP 1038 was based on the historic standard Fed-Std-376B: 1993, Preferred Metric Units for General Use by the Federal Government.

NIST SI Measurement System Chart

NIST SI Measurement System Chart
Edition: 2021

This publication is a 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. The Measurement League are superheroes dedicated to the fight against uncertainty, imprecision, and inaccuracy and to improving the quality of our lives and the things we build. SI Prefix symbols are featured in the chart and used to represent smaller or larger units by factors that are powers of 10. Submit hard copy requests to TheSI [at] (TheSI[at]nist[dot]gov). Chart dimensions: 216 mm by 279 mm (8.5 in by 11 in).

homework helper designed to be used in the classroom or at home as an approximate unit conversion factor guide
Credit: NIST

 Metric Pyramid
NIST LC 1140
Edition: 2002

This resource, once printed and assembled, creates a "homework helper designed to be used in the classroom or at home as an approximate unit conversion factor guide.

Metric Style Guide

Metric Style Guide
NIST LC 1137 (PDF)
Edition: 1997

The "Metric Style Guide" addresses how to use metric units in written and verbal communication by addressing the metric prefixes, proper spelling of terms, how to make conversions, use of symbols, plurals, pronunciation, and decimal points. (Out of Print).

Black and white images: oval image, Metric Program contact information; definition of kilogram in U.S. pounds; meter in approximate length in U.S. yard; millileter size compared to U.S. dime; kilometer compared to mile; common units and prefixes listed; gram compared to weight of paperclip; liter compared to quart; NIST logo
Credit: NIST

Metric Bookmark
Edition: 2001

This printable metric unit bookmark, when printed will create four bookmarks.

Printable metric card with NIST logo, and fill in the blank paragraph, contact information for NIST Metric Program, 8 cm ruler image
Credit: NIST

Metric Children's Activity Card
Edition: 2001

This resource template is designed to allow students to record length (centimeter), mass (kilogram), and temperature (degree Celsius) measurements.

U.S. Manufactures with Product Conforming to Metric Standards: An Analysis

U.S. Manufactures with Product Conforming to Metric Standards: An Analysis (PDF)
Edition: 1999

This report, prepared for the Metric Program, is the result of research into and analysis of the unique data on U.S. manufacturers maintained by the Thomas Publishing Company.

The purpose of this research and analysis is to provide the Metric Program with insights as to the current extent of compliance to metric standards among U.S. industrial product manufacturers. This report gives a "snapshot" of the degree of availability of metric standard products of interest to original equipment manufacturers serving both domestic and overseas markets. (Out of Print).

Report to the Congress. A Metric America: A decision whose time has come.

Report to the Congress. A Metric America: A decision whose time has come.
NBS SP 345 (PDF)
Edition: July 1971

In 1968, Congress authorized the Secretary of Commerce to make a study to determine the advantages and disadvantages of increased use of the metric system in the United States (Public Law 90-472). This report and 12-volume substudy report series contributed to passage of the Metric Conversion Act of 1975 (15 U.S.C. 205a et seq., amended by the Omnibus Trade and Competitiveness Act of 1988). (Out of Print).

The International Bureau of Weights and Measures (1875 to 1975)

The International Bureau of Weights and Measures (1875 to 1975)
NBS SP 420 (PDF)
Edition: July 1975

This publication provides a history of the first century (1875-1975) of the International Bureau of Weights and Measures (BIPM, Bureau International des Poids et Mesures), including the history of the Meter Convention (Convention du Mètre) and the SI.  (Out of Print).


Note: To request hard copies of NIST SI publications, contact the thesi [at] (Metric Program).


Created November 4, 2009, Updated February 5, 2024