Length:
1 in = 25.4 mm
1 ft = 0.3048 m
1 m = 1.09361 yd
1 km = 1093.61 yd = 0.621371 miles
1 mile = 1.60934 km = 1760 yd
1 yd = 0.9144 m
Area:
1 in2 = 654.16 mm2
1 ft2 = 0.092903 m2
1 m2 = 1.19599 yd2 = 10.76391 ft2
1 mm2 = 0.00155 in2
1 yd2 = 0.836127 m2
1 acre = 4840 yd2 = 4046.86 m2 = 0.404686 m2 hectare
1 hectare = 2.47105 acre = 10 000 m2
Volume:
1 cm3 = 0.061024 in3
1 dm3 = 11 (litre) = 0.035315 ft3
1 ft3 = 0.028317 m3 = 6.22883 gal (imp)
1 gal (imp) = 4.54609 l (litre)
1 in3 = 16.3871 cm3
1 l (litre) = 1 dm3 = 0.001 m3 = 0.21997 gal (imp)
1 m3 = 1.30795 yd3 = 35.31467 ft3
1 pt (pint) = 0.568261 l
1 US gal = 3.78541 l = 0.832674 gal (imp)
Tables and general data 3
1 ft3/min (cfm) = 1.699 m3/h
1 ft3/sec = 28.31681/s
Mass:
1 lb (pound) = 0.453592 kg
1 cwt = 50.802 kg
1 kg = 2.20462 lb
1 oz = 28.349 gm
1 ton = 2240 lb = 1.01605 t (tonne) = 1016.05 kg
1 ton (US) = 2000 lb = 907.185 kg
Force:
1 kgf = 9.80665 N = 2.20462 lbf = 1 kp (kilopond)
1 lbf = 4.44822 N
1 pdl (poundal) = 0.138255 N
Density:
1 kgf/m3 = 0.062428 lb/ft3
1 lb/ft3 = 16.0185 kg/m3
1 g/cm3 = 1000 kg/m3
Pressure, stress:
1 kgf/cm2 = 98.0665 kPa (kN/m2)
1 kgf/mm2 = 9.80665 N/mm2 = 1422.33 lbf/in2 = 0.63497 tonf/in2
1 lbf/in2 (psi) = 6.89476 kPa (kN/m2)
1 Pa (N/m2) = 0.000145038 lbf/in2
1 in w.g. (in H2O) = 249.089 Pa
1 N/mm2 = 1 MPa = 145.038 lbf/in2 = 0.06475 tonf/in2
= 0.10197 kgf/cm2
Power:
1 kW = 3412 Btu/hr
1 hp (horsepower) = 0.745700 kW
Energy, heat, work:
1 Btu = 1.05506 kJ
1 cal = 4.1868 J
1 kWh = 3.6 MJ = 3412 Btu
1 therm = 100 000 Btu = 105.506 MJ
1 kJ = 0.277778 W.h
Specific heat capacity, heat transfer:
1 cal/g°C = 1 kcal/kg°C = 4186.8 J/kg.K
1 Btu/lb°F = 4186.8 J/kg.K
1 Btu/h = 0.293071 W
1 cal/cm.s°C = 418.68 W/m.K (thermal conductivity)
4 Foseco Ferrous Foundryman’s Handbook
1 Btu.in/ft2h°F = 0.144228 W/m.K (thermal conductivity)
1 Btu/ft2h°F = 5.67826 W/m2.K (heat transfer coeff.)
Miscellaneous:
1 std.atmos. = 101.325 kPa = 760 mm Hg = 1.01325 bar
1 bar = 100 kPa = 14.5038 lbf/in2
1 cP (centipoise) = 1 mPa.s
1 cSt (centistoke) = 1 mm2/s
1 cycle/s = 1 Hz (Hertz)
1 hp = 745.7 W
Useful approximations:
1 Btu = 1 kJ 1 kg = 21/4 lb
1 ft = 30 cm 1 kgf = 10 N
1 gal = 41/2 l 1 std atmos. = 1 bar
1 ha = 21/2 acre 1 km = 5/8 mile
1 hp = 3/4 kW 1 litre = 13/4 pint
1 in = 25 mm 1 lbf = 41/2 N
1 therm = 100 MJ 1 yd = 0.9 m
1 tonf/in2 = 15 N/mm2
1 psi (lbf/in2) = 7 kPa
1 N (newton) = the weight of a small apple!
Temperature:
°F = 1.8 × °C + 32
°C =(°F – 32)/1.8
0°C (Celsius) = 273.15 K (Kelvin)