// Construct
Length meter = Length.FromMeters(1);
Length twoMeters = new Length(2, LengthUnit.Meter);
// Convert
double cm = meter.Centimeters; // 100
double yards = meter.Yards; // 1.09361
double feet = meter.Feet; // 3.28084
double inches = meter.Inches; // 39.3701
// Pass quantity types instead of values to avoid conversion mistakes and communicate intent
string PrintPersonWeight(Mass weight)
{
// Compile error! Newtons belong to Force, not Mass. A common source of confusion.
double weightNewtons = weight.Newtons;
// Convert to the unit of choice - when you need it
return $"You weigh {weight.Kilograms:F1} kg.";
}
The culture for abbreviations defaults to Thread.CurrentCulture and falls back to US English if not defined. Thread.CurrentCulture affects number formatting unless a custom culture is specified. The relevant methods are:
ToString()
GetAbbreviation()
Parse/TryParse()
ParseUnit/TryParseUnit()
var usEnglish = new CultureInfo("en-US");
var russian = new CultureInfo("ru-RU");
var oneKg = Mass.FromKilograms(1);
// ToString() uses CurrentCulture for abbreviation language number formatting. This is consistent with the behavior of the .NET Framework,
// where DateTime.ToString() uses CurrentCulture for the whole string, likely because mixing an english date format with a russian month name might be confusing.
Thread.CurrentThread.CurrentCulture = russian;
string kgRu = oneKg.ToString(); // "1 кг"
// ToString() with specific culture and custom string format pattern
string mgUs = oneKg.ToUnit(MassUnit.Milligram).ToString(usEnglish, "unit: {1}, value: {0:F2}"); // "unit: mg, value: 1.00"
string mgRu = oneKg.ToUnit(MassUnit.Milligram).ToString(russian, "unit: {1}, value: {0:F2}"); // "unit: мг, value: 1,00"
// Parse measurement from string
Mass kg = Mass.Parse("1.0 kg", usEnglish);
// Parse unit from string, a unit can have multiple abbreviations
RotationalSpeedUnit rpm1 = RotationalSpeed.ParseUnit("rpm"); // RotationalSpeedUnit.RevolutionPerMinute
RotationalSpeedUnit rpm2 = RotationalSpeed.ParseUnit("r/min"); // RotationalSpeedUnit.RevolutionPerMinute
// Get default abbreviation for a unit, the first if more than one is defined in Length.json for Kilogram unit
string kgAbbreviation = Mass.GetAbbreviation(MassUnit.Kilogram); // "kg"
Gotcha: AmbiguousUnitParseException
Some units of a quantity have the same abbreviation, which means .Parse() is not able to know what unit you wanted.
Unfortunately there is no built-in way to avoid this, either you need to ensure you don't pass in input that cannot be parsed or you need to write your own parser that has more knowledge of preferred units or maybe only a subset of the units.
Example:
Length.Parse("1 pt") throws AmbiguousUnitParseException with message Cannot parse "pt" since it could be either of these: DtpPoint, PrinterPoint.
Dynamically Parse Quantities and Convert to Units
Sometimes you need to work with quantities and units at runtime, such as parsing user input.
There are a handful of classes to help with this:
Quantity for parsing and constructing quantities as well as looking up units, names and quantity information dynamically
UnitConverter for converting values to a different unit, with only strings or enum values
UnitParser for parsing unit abbreviation strings, such as "cm" to LengthUnit.Centimeter
Enumerate quantities and units
Quantity is the go-to class for looking up information about quantities at runtime.
string[] Quantity.Names; // ["Length", "Mass", ...]
QuantityType[] Quantity.Types; // [QuantityType.Length, QuantityType.Mass, ...]
QuantityInfo[] Quantity.Infos; // Information about all quantities and their units, types, values etc., see more below
QuantityInfo Quantity.GetInfo(QuantityType.Length); // Get information about Length
Information about quantity type
QuantityInfo makes it easy to enumerate names, units, types and values for the quantity type.
This is useful for populating lists of quantities and units for the user to choose.
QuantityInfo lengthInfo = Quantity.GetInfo(QuantityType.Length); // You can get it statically here
lengthInfo = Length.Info; // or statically per quantity
lengthInfo = Length.Zero.QuantityInfo; // or dynamically from quantity instances
lengthInfo.Name; // "Length"
lengthInfo.QuantityType; // QuantityType.Length
lengthInfo.UnitNames; // ["Centimeter", "Meter", ...]
lengthInfo.Units; // [LengthUnit.Centimeter, LengthUnit.Meter, ...]
lengthInfo.UnitType; // typeof(LengthUnit)
lengthInfo.ValueType; // typeof(Length)
lengthInfo.Zero; // Length.Zero
Construct quantity
All you need is the value and the unit enum value.
IQuantity quantity = Quantity.From(3, LengthUnit.Centimeter); // Length
if (Quantity.TryFrom(3, LengthUnit.Centimeter, out IQuantity quantity2))
{
}
Parse quantity
Parse any string to a quantity instance of the given the quantity type.
IQuantity quantity = Quantity.Parse(typeof(Length), "3 cm"); // Length
if (Quantity.TryParse(typeof(Length), "3cm", out IQuantity quantity2)
{
}
Parse unit
UnitParser parses unit abbreviation strings to unit enum values.
Enum unit = UnitParser.Default.Parse("cm", typeof(LengthUnit)); // LengthUnit.Centimeter
if (UnitParser.Default.TryParse("cm", typeof(LengthUnit), out Enum unit2))
{
// Use unit2 as LengthUnit.Centimeter
}
Convert quantity to unit - IQuantity and Enum
Convert any IQuantity instance to a different unit by providing a target unit enum value.
// Assume these are passed in at runtime, we don't know their values or type
Enum userSelectedUnit = LengthUnit.Millimeter;
IQuantity quantity = Length.FromCentimeters(3);
// Later we convert to a unit
quantity.ToUnit(userSelectedUnit).Value; // 30
quantity.ToUnit(userSelectedUnit).Unit; // LengthUnit.Millimeter
quantity.ToUnit(userSelectedUnit).ToString(); // "30 mm"
quantity.ToUnit(PressureUnit.Pascal); // Throws exception, not compatible
quantity.As(userSelectedUnit); // 30
Convert quantity to unit - From/To Enums
Useful when populating lists with unit enum values for the user to choose.
UnitConverter.Convert(1, LengthUnit.Centimeter, LengthUnit.Millimeter); // 10 mm
Convert quantity to unit - Names or abbreviation strings
Sometimes you only have strings to work with, that works too!
UnitConverter.ConvertByName(1, "Length", "Centimeter", "Millimeter"); // 10 mm
UnitConverter.ConvertByAbbreviation(1, "Length", "cm", "mm"); // 10 mm
Custom units
Units.NET allows you to add your own units and quantities at runtime, to represent as IQuantity and reusing Units.NET for parsing and converting between units.
Map between unit enum values and unit abbreviations
// Map unit enum values to unit abbreviations
UnitAbbreviationsCache.Default.MapUnitToDefaultAbbreviation(HowMuchUnit.Some, "sm");
UnitAbbreviationsCache.Default.GetDefaultAbbreviation(HowMuchUnit.Some); // "sm"
UnitParser.Default.Parse<HowMuchUnit>("sm"); // HowMuchUnit.Some
Convert between units of custom quantity
var unitConverter = UnitConverter.Default;
unitConverter.SetConversionFunction<HowMuch>(HowMuchUnit.Lots, HowMuchUnit.Some, x => new HowMuch(x.Value * 2, HowMuchUnit.Some));
unitConverter.SetConversionFunction<HowMuch>(HowMuchUnit.Tons, HowMuchUnit.Lots, x => new HowMuch(x.Value * 10, HowMuchUnit.Lots));
unitConverter.SetConversionFunction<HowMuch>(HowMuchUnit.Tons, HowMuchUnit.Some, x => new HowMuch(x.Value * 20, HowMuchUnit.Some));
var from = new HowMuch(10, HowMuchUnit.Tons);
IQuantity Convert(HowMuchUnit toUnit) => unitConverter.GetConversionFunction<HowMuch>(from.Unit, toUnit)(from);
Console.WriteLine($"Convert 10 tons to:");
Console.WriteLine(Convert(HowMuchUnit.Some)); // 200 sm
Console.WriteLine(Convert(HowMuchUnit.Lots)); // 100 lts
Console.WriteLine(Convert(HowMuchUnit.Tons)); // 10 tns
Example: Unit converter app
Source code for Samples/UnitConverter.Wpf Download (release 2018-11-09 for Windows)
This example shows how you can create a dynamic unit converter, where the user selects the quantity to convert, such as Temperature, then selects to convert from DegreeCelsius to DegreeFahrenheit and types in a numeric value for how many degrees Celsius to convert.
The quantity list box contains QuantityType values such as QuantityType.Length and the two unit list boxes contain Enum values, such as LengthUnit.Meter.
Populate quantity selector
Use Quantity to enumerate all quantity type enum values, such as QuantityType.Length and QuantityType.Mass.
Using UnitConverter to convert by unit enum values as given by the list selection "Length" and unit names like "Centimeter" and "Meter".
double convertedValue = UnitConverter.Convert(
FromValue, // numeric value
SelectedFromUnit.UnitEnumValue, // Enum, such as LengthUnit.Meter
SelectedToUnit.UnitEnumValue); // Enum, such as LengthUnit.Centimeter
Example: WPF app using IValueConverter to parse quantities from input
The purpose of this app is to show how to create an IValueConverter in order to bind XAML to quantities.
Precision and Accuracy
A base unit is chosen for each unit class, represented by a double value (64-bit), and all conversions go via this unit. This means that there will always be a small error in both representing other units than the base unit as well as converting between units.
Units.NET was intended for convenience and ease of use, not highly accurate conversions, but I am open to suggestions for improvements.
The tests accept an error up to 1E-5 for most units added so far. Exceptions include units like Teaspoon, where the base unit cubic meter is a lot bigger. In many usecases this is sufficient, but for others this may be a showstopper and something you need to be aware of.
Build and test pull requests, notifies on success or error
Deploy nugets on master branch, if nuspec versions changed
Who are Using This?
It would be awesome to know who are using this library. If you would like your project listed here, create an issue or edit the README.md and send a pull request. Max logo size is 300x35 pixels and should be in .png, .gif or .jpg formats.
Swing Catalyst and Motion Catalyst, Norway
Sports performance applications for Windows and iOS, that combine high-speed video with sensor data to bring facts into your training and visualize the invisible forces at work
Units.NET started here in 2007 when reading strain gauge measurements from force plates and has been very useful in integrating a number of different sensor types into our software and presenting the data in the user's preferred culture and units.
Award-winning performers and composers put everything they’ve got into their music. PK Sound makes sure their fans will hear it all – brilliantly, precisely, consistently.
PK Sound uses UnitsNet in Kontrol - the remote control counterpart to Trinity, the world's only robotic line array solution.
Microsoft.IoT.Devices extends Windows IoT Core and makes it easier to support devices like sensors and displays. It provides event-driven access for many digital and analog devices and even provides specialized wrappers for devices like joystick, rotary encoder and graphics display.
Software for creating printable hex maps for use in pen and paper RPGs. Both
a user-friendly app and a high-level library for generating labelled hexmaps.
ANSYS Discovery Live provides instantaneous 3D simulation, tightly coupled with direct geometry modeling, to enable interactive design exploration and rapid product innovation. It is an interactive experience in which you can manipulate geometry, material types or physics inputs, then instantaneously see changes in performance.
Stargen is a decades old software to create realistic planets and satellites from a given Star. It's based on work from various scientists and been used for years. Primoris Sigma Stargen is a C# port of the utility that makes it a Framework to extend it with new algorithms for planetary formation and physics equations.
Harrington Hoists, Inc. (A Subsidiary of KITO Americas, Inc.)
Harrington Hoists, Inc. is located in Manheim, PA, Elizabethtown, PA, South Holland, IL and Corona, CA. Harrington is a leading manufacturer of manual, electric and air chain hoists as well as wire rope hoists and crane products serving the North American material handling industry.
Harrington uses UnitsNet in their internal software to perform many different calculations related to crane dimensioning, girder strength, electrical safety verification, etc.
The Structural Analysis Format (SAF) has been created to allow structural engineering applications to exchange data using a straight forward and simple to understand format.
While inspired by IFC, SAF has its benefits that it's easily modifyable by the end-user (it's an xlsx file), well documented and easy to understand.
UnitsNet is used by the SDK provided by SCIA to facilitate import / export between metric & imperial systems
