Units.NET

Everyone have written their share of trivial conversions - or less obvious ones where you need to Google that magic constant.

Stop littering your code with unnecessary calculations. Units.NET gives you all the common units of measurement and the conversions between them. It is light-weight, unit tested and supports PCL.

Install

To install Units.NET, run the following command in the Package Manager Console or go to the NuGet site for the complete relase history.

Build Targets:

• .NET 3.5 Client
• Silverlight 4
• WinRT / .NET Core 4.5
• Portable Class Library (.NET 4.0 + Silverlight 4 + Windows Phone 7 + Xbox 360)

Features

• Immutable structs for units of measurement, such as Length, Mass, Force and Pressure. See full list here.
• Convert between most popular units in the metric and imperial systems. See full list here.
• Choose between static (Length, Mass, Force etc.) or dynamic (UnitValue) representations for units of measurement.
• Parse abbreviation string to unit taking culture into account.
• Get abbreviation string for unit in different cultures.

Static Representation and Explicit Conversion

// Stop postfixing your variables and method names with the unit...doubleweightKg=GetPersonWeightInKg();UpdatePersonWeightInGrams(weightKg*1000);// ...and start using a static representation for the measurement then // explicitly convert to the unit of choice - when you need it.Massweight=GetPersonWeight();UpdatePersonWeightInGrams(weight.Grams);// Convert between compatible units of measurement...ForcescaleMeasurement=Force.FromNewtons(850);MasspersonWeight=Mass.FromGravitationalForce(scaleMeasurement);doubleweightKg=personWeight.Kilograms;// ...while avoiding confusing conversions, such as between weight and mass.Massweight=GetPersonWeight();doubleweightNewtons=weight.Newtons;// No such thing.// Some popular conversions.Lengthmeter=Length.FromMeters(1);doublecm=meter.Centimeters;// 100doubleyards=meter.Yards;// 1.09361doublefeet=meter.Feet;// 3.28084doubleinches=meter.Inches;// 39.3701Pressurep=Pressure.FromPascal(1);doublekpa=p.KiloPascals;// 1×10-3doublebar=p.Bars;// 1×10-5doubleatm=p.Atmosphere;// 9.86923267×10-6doublepsi=p.Psi;// 1.45037738×10-4

Dynamic Representation and Conversion

// Explicitlydoublem=UnitConverter.Convert(1,Unit.Kilometer,Unit.Meter);// 1000doublemi=UnitConverter.Convert(1,Unit.Kilometer,Unit.Mile);// 0.621371doubleyds=UnitConverter.Convert(1,Unit.Meter,Unit.Yard);// 1.09361// Or dynamically.UnitValueval=GetUnknownValueAndUnit();// Returns false if conversion was not possible.doublecm;val.TryConvert(Unit.Centimeter,outcm);

Helper Methods to Construct Measurements

varf=Force.FromPressureByArea(Pressurep,Length2darea);varf=Force.FromMassAcceleration(Massmass,doublemetersPerSecondSquared);

Parse and Get Culture-Specific Abbreviations

varus=newCultureInfo("en-US");varnorwegian=newCultureInfo("nb-NO");Unit.Tablespoon==UnitSystem.Create(us).Parse("tbsp");Unit.Tablespoon==UnitSystem.Create(norwegian).Parse("ss");"T"==UnitSystem.GetDefaultAbbreviation(Unit.Tablespoon,us);"ss"==UnitSystem.GetDefaultAbbreviation(Unit.Tablespoon,norwegian);

Precision

A base unit is chosen for all classes of units, which is represented by a double value (64-bit), and all conversions go via this unit. This means there will always be a small error in both representing other units than the base unit as well as converting between units.

In the unit tests I accept an error less than 1E-5 for all units I've added so far. In many usecases this is sufficient, but for some usecases this is definitely not OK and something you need to be aware of. For more details, see Precision.

What It Is Not

• It is not an equation solver.
• It does not figure out the units after a calculation.

Frequently Asked Questions

Q: Why is the conversion not perfectly accurate? As an example, when converting 1 PoundForce (lbF) to KilogramForce (kgF) I expected the result to be 0.45359237 and instead I got​0.45359240790780886 using the following for the conversion:

doublekg=UnitConverter.Convert(1,Unit.PoundForce,Unit.KilogramForce);

A: There are a few concerns here.

• For several unit conversions there is no one perfect answer. Some units depend on constants such as the standard gravity, where different precisions are used in different contexts. Other constants depend on the environment, such as the temperature or altitude.
• By design, Units.NET was not intended for high-accuracy conversions but rather convenience and simplicity. I am open to suggestions for improvements. If you want to know more, see the Precision article.

Want To Contribute?

This project is still early and many units and conversions are not yet covered. If you are missing something, please help by contributing or ask for it by creating an issue.

Before adding new units, please read the wiki on Adding a New Unit. Other than that, we could always use more/better tests and documentation.

Contact me if you have any questions.