Engineering Conversions Constants

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The following tables provide conversion constants for length, area, volumes, liquid measures, weights measures and more.

 Abbreviations may stand for singular or plural usage cm = centimeter cu. = cubic ft. = foot gal. = gallon (US) g. = gram Imp. = Imperial in. = inch kg. = kilogram km. = kilometer l. = liter lb. = pound m. = meter mi. = mile oz. = ounce qt. = quart std. = standard US = United States yd. = yard

 LENGTH MEASURES Common Usage Reciprocal Value 1 ft. = 12 in.. 1 in. = 0.0833 ft. 1 yd. = 3 ft. 1 ft. = 0.3333 yd. 1 rod = 5.5000 yd. 1 yd. = 0.1818 rods 1 furlong = 40 rods 1 rod = 0.0250 furlongs 1 mile = 8 furlongs 1 furlong = 0.1250 mi. 1 mi. = 5,280 ft. 1 ft. = 0.000189 mi. 1 mi. = 1,760 yd. 1 yd. = 0.000568 mi. 1 fathom = 6 ft. 1 ft. = 0.1667 fathom 120 fathoms = 1 cable 1 cable = 0.00833 fathoms 1 league = 3 mi. 1 mi. = 0.3333 leagues 1 nautical mi. = 6076.11 ft. 1 ft. = 0.000165 nautical mi. 1 hand = 4 in. (equestrian) 1 in. = 0.2500 hands METRIC 1 in. = 2.54 cm. 1 cm. = 0.3937 in. 1 ft. = 30.48 cm. 1 cm. = 0.0328 ft. 1 m. = 3.2808 ft. 1 ft. = 0.3048 m. 1 m. = 39.37 in. 1 in. = 0.0254 m. 1 m. = 1.0936 yd. 1 yd. = 0.9144 m. 1 rod = 5.029 m. 1 m. = 0.1988 rod 1 km = 1000 m. 1 m. = 0.001 km. 1 km = 0.621 mi. 1 mi. = 1.6103 km.

 SQUARE MEASURES Common Usage Reciprocal Value 1 sq. ft. = 144 sq. in. 1 sq. in = .006944 sq. ft. 1 sq. yd. = 9 sq. ft. 1 sq. ft. = 0.1111 sq. yd. 1 sq. rod = 30.25 sq. yd. 1 sq. yd. = 0.0331 sq. rods 1 sq. mi. = 640 acres 1 acre = 0.0016 sq. mi. METRIC 1 sq. cm. = 0.1550 sq. in. 1 sq. in. = 6.452 sq. cm. 1 sq. ft. = 0.0929 sq. m. 1 sq. m. = 10.7643 sq. ft. 1 sq. m. = 1.196 sq. yd. 1 sq. yd. = 0.8361 sq. m. 1 hectare = 2.47 acres 1 acre = 0.4049 hectares 1 sq. km. = 0.386 sq. mi. 1 sq. mi. = 2.59 sq. km.

 CUBIC & VOLUME MEASURES Common Usage Reciprocal Value 1 cu. ft. = 1,728 cu. in 1 cu. in. = 0.0005787 cu. ft. 1 cu. yd. = 27 cu. ft. 1 cu. ft. = 0.0370 cu. yd. 1 cord (wood) = 128 cu. ft. 1 cu. ft. = 0.0078 cord 1 US std. gal. = 231 cu. in. 1 cu. in. = 0.00433 US std. gal. METRIC 1 cu. in. = 16.39 cu. cm. 1 cu. cm. = 0.0610 cu. in. 1 cu. m. = 35.3357 cu. ft. 1 cu. ft. = 0.0283 cu. m. 1 cu. m. = 1.308 cu. yd. 1 cu. yd. = 0.7646 cu. m. DRY MEASURES 1 qt. = 2 pints 1 pint = 0.5000 qt. 1 peck = 8 qt. 1 qt. = 0.1250 peck 1 bushel = 4 pecks 1 peck = 0.2500 bushels METRIC 1 qt. dry = 1.101 l. 1 l. = 0.908 qt. dry 1 peck = 8.810 l. 1 l. = 0.1135 peck 1 hectoliter = 2.8375 bushels 1 bushel = 0.3524 hectoliters LIQUID MEASURES 1 pint = 2 cup 1 cup = 0.5000 pints 1 qt. = 2 pints 1 pints = 0.5000 qt. 1 gal.. = 4 qt. 1 qt. = 0.2500 gal. 1 gal.. = 8 pints 1 pint = 0.125000 gal.. 1 barrel = 31.5 gal.. 1 gal.. = 0.0317 barrel IMPERIAL & METRIC LIQUID MEASURE 1 US gal.. = 0.833 Imp. gal.. 1 Imp. gal.. = 1.201 US gal.. 1 Imp. gal.. = 4.546 l. 1 l. = 0.2200 Imp. gal.. 1 l. = 0.264 US gal.. 1 US gal.. = 3.7879 l. 1 l. = 1.0567 qt. liquid 1 qt. liquid = 0.9463 l. 1 gal.. = 3.7854 l. 1 l. = 0.2642 gal..

 WEIGHT MEASURES Common Usage Reciprocal Value 1 lb. = 16 oz. 1 oz. = 0.0625 lb. 1 ton = 2000 lb. 1 lb. = 0.0005 ton METRIC 1 oz. = 28.35 g. 1 gr. = 0.03527 oz. 1 kg = 1000 gm 1 gr. = 0.001 kg. 1 lb. = 0.4536 kg. 1 kg. = 2.2046 lb. 1 metric ton = 0.9842 English ton 1 English ton = 1.016 metric tons

 Temperature Celsius or Centigrade Fahrenheit 1 degree Celsius (C) = 5/9 x (F - 32) (9/5 x C) + 32 = 1 degree Fahrenheit (F)

Air Density Calculation

Std Air Density = 1.22556 and is defined at 59.0F degrees, 0.0% humidity, and 29.92 inches on the barometer.

Temp C = (Temp-32.0) * 5.0 / 9.0;
Temp K = Temp C + 273.0;
Baro mb = Barometer / (29.92 / 1013.0);
Baro pa = Baro_mb * 100.0;
Saturation Pressure mb = 6.11 * pow(10,(7.5*Temp C)/(237.7+Temp_c));
Vapor Pressure mb = Humidity * Saturation Pressure mb / 100.0;
Temp Virtual K = Temp K / (1.0 - (Vapor Pressure mb/Baro_mb)*(1.-0.622))// D = P/(T*R)
Air Density = Baro_pa / (Temp Virtual_k*GasConstant)% Std Density = Air Density/Std Air Density*100

Thermal Conductivity Conversions:

1 cal/cm2/cm/sec/C = 10.63 watts/in - C

117 BTU/(hr-ft-F) x (.293 watt-hr/BTU) x (1.8F/C) x (ft/12 in.) = 5.14 watts/in - C
or
117 Btu / (hr-ft-F) x .04395 watt-hr-F-ft/(Btu=C - in) = 5.14 watts/in-C