NCalc is a fast, lightweight expression evaluator for .NET. It parses and evaluates mathematical and logical expressions with literals, operators, parameters, built-in functions, and custom functions.

NCalc targets modern .NET, .NET Standard 2.0, and .NET Framework 4.8.

Start with the NCalc docs for the full language reference, runtime options, plugins, and API reference.

Useful entry points:

• Language reference
• Evaluation options
• Runtime features
• Extensibility and plugins

Use NCalc.Core for the expression engine:

dotnet add package NCalc.Core

Add optional packages only when you need them:

dotnet add package NCalc.LambdaCompilation
dotnet add package NCalc.DependencyInjection

using NCalc;

var result = new Expression("2 + 3 * 5").Evaluate();
// 17

var expression = new Expression("Round(Pow([x], 2) + [offset], 2)");
expression.Parameters["x"] = 3.14;
expression.Parameters["offset"] = 10;

var result = expression.Evaluate();
// 19.86

var expression = new Expression("SecretOperation(3, 6)");
expression.Functions["SecretOperation"] = args =>
    (int)args.Evaluate(0) + (int)args.Evaluate(1);

var result = expression.Evaluate();
// 9

Install NCalc.LambdaCompilation first.

using NCalc.LambdaCompilation;

var expression = new Expression("1 + 2");
Func<int> function = expression.ToLambda<int>();

var result = function();
// 3

For data types, operators, built-in functions, async evaluation, caching, expression serialization, and advanced configuration, check the docs.

Open an issue for bugs or usage problems. Include the expression, the expected result, the actual result, and your NCalc version.

• How to execute mathematical expressions in a string in .NET
• State of the Art Expression Evaluation

Using NCalc? Create a PR and add your project here!

NCalc uses Nerdbank.GitVersioning. Each library build can be traced back to the original git commit. Read more in the release documentation.