Copyright Goodheart-Willcox Co., Inc. May not be reproduced or posted to a publicly accessible website. Chapter 5 Measurement 83 5.9 Measurement Conversions In the performance of HVACR services, it may be necessary to convert from US Customary measurement units to SI measurement units and vice versa. Many conversion factor lists are available in print format in pocket manuals and troubleshooting guides. Conversion apps are also available for electronic devices. 5.9.1 Linear Measurement Conversions Linear Measurement Conversion US Customary Multiply by: SI To get: To convert from: inches 25.4 millimeters inches 2.54 centimeters inches 0.0254 meters feet 304.8 millimeters feet 30.48 centimeters feet 0.3048 meters feet 0.0003048 kilometers SI Multiply by: US Customary To get: To convert from: millimeters 0.03937 inches centimeters 0.3937 inches meters 39.37 inches millimeters 0.003281 feet centimeters 0.03281 feet meters 3.281 feet kilometers 3281 feet Goodheart-Willcox Publisher Use of the chart shown allows for the conversion of varying units of measurement. For example, if 8″ (inches) needs to be converted to millimeters (mm), the chart shows to multiply the 8″ by 25.4 to determine the millimeter equivalent. 8″ × 25.40 = 203.20 mm Thus 8″ equals 203.2 mm. To convert millimeters to inches, the chart shows a multiplier of 0.03937. 203.20 mm × 0.03937 = 7.9999840″ Thus, 203.2 mm equals 7.9999″, which can be rounded off to 8″. 5