See also Constants

Energy and Power Conversions
1kWh 3.6 × 106 J
1 hp (horsepower) 746 W
1 Btu 1.055 kJ
Time Conversions
1 year 8765.8 hours
1 hour 3600 sec
1 year 3.157 x 107 sec
Solar Radiation Conversions
1 kWh/m2 1 Peak Sun Hour
1 kWh/m23.6 MJ/m2
1 kWh/m20.0116 Langley
1 kWh/m2860 cal/m2
1 MJ/m2/day 0.01157 kW/m2
1 kW/m2 100 mW/cm2
Miscellaneous
1 ft2 0.093 m2

Standard SI prefixes

Symbol Prefix Factor
Ttera1012
Ggiga109
Mmega106
kkilo103
ccenti10-2
mmilli10-3
µmicron10-6
nnano10-9
ppico10-12