Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Weights & measures


NIST works to improve the accuracy of measurements, enhance consumer protection, foster fair competition, and facilitate economic growth and trade through technical activities that promote uniformity in national and international legal metrology laws, regulations, standards, test procedures and enforcement.

The Research

Projects & Programs

International System of Units (SI)

The International System of Units (SI) provides definitions of units of measurement that are widely accepted in science and technology and which set measurement

Additional Resources Links


stainless steel weights

White Cat Hair on Black Pants: International Study Measures Stability of Precision Masses to Benefit Trade

weights and measures composite image

Worth the Weight: New International Guidelines Published for Manufacturing Load Cells

A streaked image of a taxi and a dark car driving in Times Square, New York City street at night.

New Standard Aims to Ensure Accurate Fares in Both Ride-Hailing Technology and Traditional Taxi Services

Upcoming Events