Inputting Units

Nearly all U.S., English, Imperial and metric units are included along with their common prefixes and abbreviations. You can therefore spell out 'kilometers' or use the 'km' abbreviation. The functions will recognize common pluralities too, e.g. 'feet' for 'foot', 'inches' for 'inch' and so on. Sometimes where there are conflicting conventions (this happens most often for abbreviations), you will need to spell out the unit you want to convert from or to. The units section has a complete list of the known units, their abbreviations and if they take prefixes.

Dimensions

When you convert between units, those units must be units of measurement of the same property. Conversion between acres and square meters is valid, since they are both measures of area. But converting between pints (a unit of volume) and feet (a unit of length) can't be done. Converting between pints and cubic feet would be fine since they are both measures of volume. 

To raise a dimension to a power you can use the ^ (carat) symbol. Negative and positive exponents are fine. You can also use the / (slash) or the word "per" to denote negative exponents.  The following units of acceleration are all valid: "meters per second per second" , "miles/hour/hour" , " miles hour^-2" , "minutes^-2 yards".

There are a number of commonly used dimensions like velocity (which is Length . Time[-1] or distance per time) built into the unit converter. See the Dimensions page for a specific list.

You can use parentheses to group terms together.

The functions can convert between any compound dimension as long as the original units and desired units are compatible. For example, to convert between poises (a unit of Absolute Viscosity which is defined as Mass per Length per Time ( Mass . Length[-1] . time[-1] ), your desired units must also have these fundamental dimensions, so a conversion from 100 poise to lb /inch / minute is fine.

For a more advanced example, take the newton, the metric measure of force, which has the fundamental unit "kg m / s / s" or 'kg m / s^2' (use the ^ sign to raise a unit to a higher power). The functions will accept and convert units so long as the dimensions agree.  With newtons it would be able to convert from 'kg m / s^s' to 'lb miles / hour^2' because the fundamental units agree.

The functions will preform the dimensional analysis between compound units for you and warn you if the conversion is not possible because the dimensions do not agree.

Excel Functions

UnitConvert (value , from_units, to_units)

Converts the value from the ‘from_units’ to the ‘to_units’.
Example: UnitConvert(1,”ounce”,”gram”) = 28.3495231
Example: UnitConvert(3,”feet”,”yard”) = 1
Exampe: UnitConvert(34.5,"miles / hour","m/s") = 15.4229

The value is expected to be a numerical value.
The from and to units should be recognized units in the same dimension.

UnitToDimension( units )

Returns the dimension that the UnitConverter Add-in believes these units to be of.
Example: UnitToDimension( “meters” ) = distance
Example: UnitToDimension( “lb” ) = mass
Example: UnitToDimension( “lumens” ) = luminesense
Example: UnitToDimension( " kg m/s^2") = force

The units argument is expected to be a recognized unit name or its abbreviation.

UnitToName( units )

Returns the long name of the unit’s abbreviation.
Example : UnitToName(“lb”) = pounds
Example : UnitToName(“km”) = kilometer

The units argument is expected to be a recognized unit name abbreviation.

PrefixToNumber( prefix )

Returns the multiplier associated with a prefix like “kilo” or “nano”
Example : PrefixToNumber( “kilo” ) = 1000
Example : PrefixToNumber(“ nano “ ) = 0.000001
The prefix argument may be the full prefix or its common abbreviation.

Use the latin character u in place of the greek letter mu ( ? ) for micron.

Error Messages

Unrecognized base units in argument ...

The function does not recognize the units you are trying to convert from or to. Refer to the units page for a complete listing of known units. If you are using an abbreviation, try using the full name of the unit.  If you can't find the unit, This e-mail address is being protected from spambots. You need JavaScript enabled to view it and we'll try to add it for you.

Dimensions do not match

You are trying to convert between mismatched dimensions, i.e., you cannot convert between time and distance. Re-examine your input and output dimension strings and make sure all the units within them are equivalent.