An official website of the United States government
Here’s how you know
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.
Different countries' approaches can lead to different definitions of the kilogram. But NIST is working with our international partners to see how we can close those tiny gaps.