converters 5 min read• Updated 2026-09-04
How to Convert Units Accurately: Metric and Imperial Standards
A reference guide to fundamental conversion factors between metric and US customary units.
Table of Contents
Standard Conversion Constants
1 inch = 2.54 centimeters (exact definition).
1 pound = 0.45359237 kilograms (exact international avoirdupois pound).
1 US fluid ounce = 29.5735 milliliters.
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