CONVERSION FACTORS (Approximate)

Quantity	Imperial Unit	Metric Unit	Imperial to	Metric to
			Metric Units	Imperial Units
Length	inch (in)	millimetre (mm) or	1 in = 25.4 mm	1 cm = 0.394 in
		centimetre (cm)
	foot (ft)	centimetre or metre (m)	1 ft = 30.5 cm	1 m = 3.28 ft
	yard (yd)	metre (m)	1yd = 0.194 m	1 m = 1.09 yd
	furlong (fur)	metre (m) or	1 fur = 201 m	1 km = 4.97 fur
		kilometre (km)
	mile	kilometre (km)	1 mile = 1.61 km	1 km = 0.621 mile
	international nautical mile		1 n mile = 1852 m	1m = 3.28 ft
	(for navigation)
Mass	ounce (oz)	gram (g)	1 oz = 28.3 g	1 g = 0.0353 oz
	pound (lb)	gram (g) or kilogram (kg)	1 lb = 454 g	1 kg = 2.20 lb
	stone	kilogram (kg)	1 stone = 6.35 kg	1 kg = 0.157 stone
	ton	tonne (t)	1 ton = 1.02 t	1 t = 0.984 ton
Area	square inch (in²)	square centimetre (cm²)	1 in² = 6.45 cm²	1 cm² = 0.155 in²
	square foot (ft²)	square centimetre (cm²) or	1 ft² = 929 cm²
		square metre (m²)		1 m² = 10.8 ft²
	square yard (yd²)	square metre (m²)	1 yd² = 0.836 m²	1 m² = 1.20 yd²
	perch (p)	square metre (m²)	1 p = 25.3 m²	1 m² = 0.0395 p
	rood (rd)	hectare (ha)	1 rd = 0.101 ha	1 ha = 9.88 rd
	acre (ac)	hectare (ha)	1 ac = 0.405 ha	1 ha = 2.47 ac
	square mile	square kilometre (km²)	1 square mile=2.59 km²	1 km²=0.386 sq.mile
Volume	cubic inch (in³)	cubic centimetre (cm³)	1 in³ = 16.4 cm³	1 cm³ = 0.0610 in³
	cubic foot (ft³)	cubic metre (m³)	1 ft³ = 0.0283 m³	1 m³ = 35.3 ft³
	cubic yard (yd³)	cubic metre (m³)	1 yd³ = 0.765 m³	1 m³ = 1.31 yd³
	bushel (bus)	cubic metre (m³)	1 bus = 0040.0364 m³	1 m³ = 27.5 bus
Volume	fluid ounce (fl oz)	millilitre	1 fl oz = 28.4 ml	1 ml = 0.0352 fl oz
(fluids)	pint (pt)	millilitre (ml) or litre (l)	1 pt = 568 ml	1 litre = 1.76 pt
	gallon (gal)	litre (l) or cubic (m³)	1 gal = 4.55 litre	1 m³ = 220 gal
	acre foot	cubic metre (m³) or	1 acre foot = 1230 m³
		megalitre (ML)	1.23 ML	1 ML= 0.811 acre foot
Force	pound – force (lbf)	newton (N)	1 lbf = 4.45 N	1 N = 0.225 lbf
	ton – force (tonf)	kilonewton (kN)	tonf = 9.96 kN	1 kN = 0.100 tonf
Pressure	pound per square inch(psi)	kilopascal (kPa)	1 psi = 6.89 kPa	1 kPa = 0.145 psi
	atmosphere (atm)	kilopascal (kPa) or	1 atm = 101 kPa
		megapascal (MPa)		1 MPa = 9.87 atm
	ton per square inch (ton/in²)	megapascal (MPa)	1 ton/in² = 15.4 MPa	1 MPa = 0.647 ton/in²
	inch of mercury (in Hg)	milibar (mb)
	(for meteorology)		1 in Hg = 33.9 mb	1 mb = 0.0295 in Hg
			1 mb = 100 Pa
Velocity	mile per hour (mph)	kilometre per hour (km/h)	1 mph = 1.61 km/h	1 km/h = 0.621 mph
	knot (kn)		= 1 kn = 1.85 km/h
	(for navigation)
Temperature	degree Fahrenheit (°F)	degree Celsius (°C)	°C = 5/9 (F – 32)	°F = 9/5 (C + 32)
Density	pound per cubic inch (lb/in³)	gram per cubic centimetre (g/cm³)	1 lb/in³ = 27.7 g/cm³	1 g/cm³=0.0361 ib/in³
		= tonne per cubic metre (t/m³)	1lb/in³ = 27.7 t/m³	1 t/m³ = 0.0361ib/in³
	ton per cubic yard	tonne per cubic metre (t/m³)	1 ton/yd³ = 1.33 t/m³	1 t/m³= 0.752 ton/yd³
Energy	British thermal unit (btu)	kilojoule (kJ)	1 Btu = 1.06 kJ	1 kJ = 0.948 Btu
	therm	megajoule (MJ)	1 therm = 106 MJ	1 MJ= 9.48x 10³ therm
	(for electrical energy)	kilowatt hour (kWh)	=kWh = 3.60 MJ
Power	horsepower (hp)	kilowatt (kW)	1 hp = 0.746 kW	1 kW = 1.34 hp
Time		second (s)
		minute (min)	1 min = 60s
		hour (h)	1 h = 3600s
Frequency	cycle per second (c/s)	hertz (Hz)	1 c/s = 1.Hz	1 Hz = 1.c/s
Angular	revolution per minute	radian per second (rad/s)	1 rpm = 0.105 rad/s	1 rad/s = 9.55 rpm.
Velocity	(rpm)		revolution per minute
			(rpm)