Approximate Conversions from U.S. Customary Measures to Metric

These approximate unit conversion factors are published as NIST SP 365, Metric Conversion Card. This wallet-size card helps users make quick, approximate unit conversions between SI (metric) units and non-SI (U.S. customary) units. It includes conversions for length, area, mass, volume, and temperature. When exact unit conversion factors are needed, NIST SP 811, Appendix B is an essential source.

Unit Conversion is a multi-step process that involves multiplication or division by a numerical factor; selection of the correct number of significant digits; and rounding. Accurate unit conversions are obtained by selecting an appropriate conversion factor (a ratio which converts one unit of measure into another without changing the quantity). Teachers and other U.S. residents may request copies of this publication by emailing theSI [at] nist.gov (theSI[at]nist[dot]gov) or by using the OWM Contacts System. You can also find classroom tips for using the NIST SP 365, Metric Conversion Card with students and download a printable PDF of the publication.

EXPLORE THE METRIC PROGRAM

Becoming Familiar with SI | Everyday Estimation | U.S. Metrication | U.S. Metrication FAQs | Prefixes | Metric Kitchen | SI Education and Training | SI Publications | Understanding Metric | Writing with Metric Units | National Metric Week | NEST-R (STEM Registry) | NIST Education Resources