# 3.17 Unit Conversion

Both SI and English units are used throughout this users guide. Tables 13-14 through 13-19 list conversion factors for common units.

Table 13-14: Length Equivalents

 Unit Equivalent Millimeter Inch Foot Meter Kilometer Mile Millimeter 1 0.03937 0.003281 0.001 1´10-6 0.621´10-6 Inch 25.4 1 0.0833 0.0254 25.40´10-6 15.78´10-6 Foot 304.8 12 1 0.3048 304.8´10-6 189.4´10-6 Meter 1,000 39.37 3.281 1 0.0010 621.4´10-6 Kilometer 1´106 39,370 3,281 1,000 1 0.6214 Mile 1.609´106 63,360 5,280 1,609 1.609 1

Note: Multiply the amount of the given unit by the value shown to obtain the amount in equivalent units (e.g., 1.50 m x 39.37 inch/m = 59.1 inch)

Table 13-15: Area Equivalents

 Unit Equivalent Sq. inch Sq. foot Sq. meter Acre Hectare Sq. mile Sq. inch 1 0.006944 645´10-6 0.16´10-6 64.5´10-9 0.25´10-9 Sq. foot 144 1 0.0929 23´10-6 9.29´10-6 35.9´10-9 Sq. meter 1,550 10.76 1 2471´10-6 0.0001 0.39´10-6 Acre 6.27´106 43,560 4,047 1 0.4047 0.001563 Hectare 15.5´106 107,639 10,000 2.471 1 0.003861 Sq. mile 4.01´109 27.88´106 2.59´106 640 259.0 1

Table 3-16: Volume Equivalents

 Equivalent Unit Cu. inch Liter U.S. gallon Cu. foot Cu. meter Acre-foot Cu. inch 1 0.01639 0.004329 578.7´10-6 16.39´10-6 13.29´10-9 Liter 61.02 1 0.2642 0.03531 0.0010 810.6´10-9 U.S. gallon 231.0 3.785 1 0.1337 0.003785 3.068´10-6 Cu. foot 1,728 28.32 7.481 1 0.02832 22.96´10-6 Cu. meter 61,020 1,000 264.2 35.31 1 810.6´10-6 Acre-foot 75.27´106 1.233´106 325,900 43,560 1,233 1

Table 3-17: Discharge Equivalents

 Unit Equivalent Gallon/min Liter/sec Acre-ft/day Cu. foot/sec Million gal/day Cu. meter/sec Gallon/min 1 0.06309 0.004419 0.002228 0.001440 63.09´10-6 Liter/sec 15.85 1 0.07005 0.03531 0.02282 0.0010 Acre-ft/day 226.3 14.28 1 0.5042 0.3259 0.01428 Cu. foot/sec 448.8 28.32 1.983 1 0.6463 0.02832 Million gal/day 694.4 43.81 3.069 1.547 1 0.04381 Cu. meter/sec 15,850 1,000 70.04 35.31 22.82 1

Table 3-18: Miscellaneous Conversions

 Dimension SI unit Multiplier Equivalent U.S. customary unit Velocity Meter/sec 3.281 Feet/second Mass Kilogram 0.06852 Slugs Force Newton 0.2248 Pound force Pressure Pascal 145.0´10-6 Pound force/sq. inch Pressure Pascal 0.02089 Pound force/sq. foot Power Watt 0.001341 Horsepower Power Watt 0.7376 Foot-pound/second Energy Joule 0.7376 Foot - pound Heat Density Calorie/sq. cm.(i.e., Langley) 3.687 BTU/sq. foot

Note: To covert from U.S. customary units to S.I. units, use the inverse of the listed multiplier (e.g., 2.0 ft/s ´ (1/3.281) = 0.61 m/s)

Table 3-19: Temperature Conversions

 Original unit Conversion formula Equivalent unit oF 5 ´ (oF – 32) / 9 oC oC 32 + (9 ´ oC / 5) oF oC oC + 273 oK oF 5 ´ (oF + 460) / 9 oK oR 5 ´ oR / 9 oK

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