A.1 Metric System Conversions

From 
To 
Multiply by: 
Mass 
ounces 
grams 
28.349 
pounds 
kilograms 
0.454 

short tons 
metric tons 
0.907 

grams 
ounces 
0.035 

kilograms 
pounds 
2.205 

metric tons 
short tons 
1.102 

Volume 
cubic metres 
cubic feet 
33.31 
Temperature 
°F 
°C 
5/9 (after subtracting 32) 
°C 
°F 
9/5 (then add 32) 

Length 
inches 
millimetres 
25.4 
feet 
centimetres 
30.48 

yards 
metres 
0.914 

miles 
kilometres 
1.609 

millimetres 
inches 
0.039 

centimetres 
inches 
0.393 

metres 
yards 
1.09 

kilometres 
miles 
0.62 

Area 
square inches 
square centimetres 
6.5 
square feet 
square metres 
0.092 

square yards 
square metres 
0.836 

square miles 
square kilometres 
2.6 

acres 
hectares 
0.404 

square centimetres 
square inches 
0.16 

square metres 
square yards 
1.195 

square kilometres 
square miles 
0.39 

hectares 
acres 
2.47 
A.2 Heat and Energy
1 kilowatthour = 
1 000 watthour 

1.3410 HPhour 

3 600 000 joules 

3 413 BTU 

860 kcals 

3.518 lb water evaporation from and at 212°F 

22.76 lb of water raised from 62 to 212°F 

1.595 kg of water evaporation from and at 100°C 

9.907 kg of water raised from 20 to 100°C 
1 atmosphere = 
14.69 lb per sq in = 1.02 kg per sq cm 
1 calorie = 
0.003968 BTU 
1 BTU = 
252 calories (gramme) (15°C) 
1 BTU = 
heat required to raise 1 lb water 1°F 
1 BTU = 
0.00039 HPhour 
1 BTU per min = 
17.6 watts 
1 cu in = 
0.01639 litres 
1 watt = 
0.00134 HP 
1 joule = 
1 wattsec 
1 HP = 
746 watts 
p = 
3.1416 