Difference between static and constant

In C#, both static and constant are used to define values that remain unchanged throughout the execution of a program. However, there are some key differences between the two.


Static is a modifier that can be applied to fields, methods, properties, and classes. When applied to a field, it means that the field belongs to the type itself rather than an instance of the type. Here are some important points to understand about static:

  1. A static field is shared among all instances of a class. It is initialized only once, and any changes made to it are reflected in all instances.
  2. Static methods can be called directly on the class without creating an instance of the class.
  3. Static properties provide a way to access and manipulate shared data across all instances of a class.
  4. Static classes can only contain static members and cannot be instantiated. They are commonly used to group related utility methods or provide global access points to shared resources.
public class MathUtils { public static double PI = 3.14159; public static int Add(int a, int b) { return a + b; } } // Usage double piValue = MathUtils.PI; // Accessing a static field int result = MathUtils.Add(5, 3); // Calling a static method


A constant is a value that is known at compile-time and remains constant throughout the execution of a program. It is declared using the const keyword and must be assigned a value at the time of declaration. Here are some important points about constants:

  1. Constants are implicitly static, meaning they belong to the type itself and not to any instance.
  2. Constants are resolved at compile-time and their values are embedded directly into the compiled code.
  3. Constants can only have simple data types such as numeric values, characters, booleans, or strings. They cannot be modified or changed during runtime.
  4. Constants are typically used for values that are known in advance and are not expected to change.
public class Circle { public const double PI = 3.14159; public double CalculateArea(double radius) { return PI * radius * radius; } } // Usage Circle circle = new Circle(); double area = circle.CalculateArea(5); // Uses the constant PI in the calculation


Static members are used for shared data or functionality among all instances of a class, while constants are used for values that remain constant throughout the execution of a program. Static members can be modified and updated, while constants are fixed and cannot be changed.