Use the upper multiplication factor to convert from a left-side quantity to the corresponding right-side quantity.
Use the lower multiplication factor to convert from a right-side quantity to the corresponding left-side quantity.

Conversions will be rounded to significant digit(s).

I have included some of the more common conversions used in hydrology and meteorology and have forgone some of the more elementary ones (such as feet to inches or meters to centimeters). The conversion factors shown have been rounded to no more than 4 significant digits;however, the full precision (as supported by your computer) is used in calculations.

These instant conversions use JavaScript, which requires a browser newer than Netscape 2.0 or Internet Explorer 2.0. If you don't have one of these browsers or another JavaScript-enabled browser, you can still use the conversion factors, but you'll have to do the math yourself.

Length Area Volume Speed Flow Temperature Pressure

Length

Area | Volume | Speed | Flow | Temperature | Pressure

To convert from ->
To get <- 		-> multiply by ->
<- multiply by <-		 -> To get
<- To convert from
Inches (in)

 2.54
0.3937
Centimeters (cm)
Feet (ft)

 0.3048
3.281
Meters (m)
Miles (mi)

 1.609
0.6214
Kilometers (km)
Nautical miles (n mi)

 1.852
0.5400
Kilometers (km)
Nautical miles (n mi)

 1.152
0.8684
Statute Miles (mi)

Area

Length | Volume | Speed | Flow | Temperature | Pressure

To convert from ->
To get <- 		-> multiply by ->
<- multiply by <-		 -> To get
<- To convert from
Square feet (ft2)

 0.09290
10.76
Square meters (m2)
Square miles (mi2)

 2.590
0.3861
Square kilometers (km2)
Square miles (mi2)

 640
0.001563
Acres (ac)
Acres (ac)

 43,560
2.296 x 10-5
Square feet (ft2)
Acres (ac)

 0.4047
2.471
Hectares (ha)

Volume

Length | Area | Speed | Flow | Temperature | Pressure

To convert from ->
To get <- 		-> multiply by ->
<- multiply by <-		 -> To get
<- To convert from
Cubic feet (ft3)

 0.02832
35.31
Cubic meters (m3)
Acre-feet (ac-ft)

 43,560
2.296 x 10-5
Cubic feet (ft3)
Acre-feet (ac-ft)

 3.259 x 105
3.069 x 10-6
Gallons (gal)
Acre-feet (ac-ft)

 1233
8.107 x 10-4
Cubic meters (m3)
Cubic feet per second - day (cfs-d)

 86,400
1.157 x 10-5
Cubic feet (ft3)
U.S. gallons (gal)

 0.1337
7.479
Cubic feet (ft3)
U.S. gallons (gal)

 3.785
0.2641
Liters (L)

Speed

Length | Area | Volume | Flow | Temperature | Pressure

To convert from ->
To get <- 		-> multiply by ->
<- multiply by <-		 -> To get
<- To convert from
Feet per second (ft/s)

 0.3048
3.281
Meters per second (m/sec)
Miles per hour (mi/hr)

 1.609
0.6214
Kilometers per hour (km/hr)
Miles per hour (mi/hr)

 0.8684
1.152
Knots (kt)
Miles per hour (mi/hr)

 0.4470
2.237
Meters per second (m/s)

Flow

Length | Area | Volume | Speed | Temperature | Pressure

To convert from ->
To get <- 		-> multiply by ->
<- multiply by <-		 -> To get
<- To convert from
Cubic feet per second (ft3/s)

 0.02832
35.31
Cubic meters per second (m3/s)
Cubic feet per second (ft3/s)

 448.8
2.228 x 10-3
Gallons per minute (gal/min)
Cubic feet per second (ft3/s)

 1.983
0.5042
Acre-feet per day (ac-ft/day)

Temperature

Length | Area | Volume | Speed | Flow | Pressure

To convert from ->
To get <- 		-> multiply by ->
<- multiply by <-		 -> To get
<- To convert from
degrees Fahrenheit (°F)

 5/9 (Tf - 32)
9/5 * Tc + 32
degrees Celsuis (°C)
degrees Celsius (°C)

 Tc + 273.15
K - 273.15
Kelvins (K)
degrees Fahrenheit (°F)

 5/9 (Tf + 459.67)
9/5 * K - 459.67
Kelvins (K)

Pressure

Length | Area | Volume | Speed | Flow | Temperature

To convert from ->
To get <- 		-> multiply by ->
<- multiply by <-		 -> To get
<- To convert from
Millibars (mb)

 0.02953
33.87
Inches of mercury (in Hg)
Millibars (mb)

 0.1000
10.00
Kilopascals (kPa)

Equivalents

1 cfs-day/mi2 = 0.03719 in of runoff
1 in of runoff/mi2 = 26.89 cfs-day = 2.323 x 106 ft3