In Dart, the const keyword is used to declare constants. Constants are values that cannot be changed after they are assigned. They are compile-time constants, meaning their values are determined at compile time rather than runtime. Using const in Dart offers several benefits:

1. Performance: Constants are evaluated at compile time, and their values are directly embedded into the compiled code. This can result in better performance compared to runtime calculations.

2. Memory Efficiency: Since constant values are known at compile time, Dart can optimize memory usage by directly embedding the values into the compiled code rather than allocating memory at runtime.

3. Readability and Maintainability: Declaring something as a constant makes it clear that its value should not change. This enhances code readability and makes it easier to reason about the behavior of the program.

Here's an example of using const in Dart:

const int x = 10;
const double pi = 3.14;
const String appName = "MyApp";

void main() {
  print(x);
  print(pi);
  print(appName);
}

In this example, x, pi, and appName are all declared as constants using the const keyword. Once assigned, their values cannot be changed during the execution of the program.