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 ( LockA locked padlock
) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
If you don't find the answer to your question on these pages, send us an email, call (301) 975-NIST, or write to Public Inquiries, NIST, 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070.
Other FAQ pages on specific topics: