# Java Program to Convert Kilometer to Millimeter and Millimeter to Kilometer

In the previous article we have discussed about Java Program to Convert Kilometer to Mile and Mile to Kilometer

In this article we will see how to convert Kilometer to Millimeter and Millimeter to Kilometer by using Java programming language.

## Java Program to Convert Kilometer to Millimeter and Millimeter to Kilometer

Before jumping into the program let’s know the relationship between Kilometer and Millimeter and how we can convert Kilometer to Millimeter and vice versa.

Generally Kilometer and Millimeter are used as unit in case of distance measurement.

1 Kilometer = 1000000 Millimeter
1 Millimeter = 1e-6 Kilometer

Formula to convert Kilometer to Millimeter.

Millimeter = Kilometer * 1000000

Formula to convert Millimeter to Kilometer.

Kilometer = Millimeter / 1000000

Let’s see different ways to convert Kilometer to Millimeter and Millimeter to Kilometer.

### Method-1: Java Program to Convert Kilometer to Millimeter and Millimeter to Kilometer By Using Static Input Value

Approach:

• Declare Kilometer and Millimeter value.
• Then convert Kilometer to Millimeter and Millimeter to Kilometer by using the formula.
• Print result.

Program:

import java.util.*;
public class Main
{
public static void main(String args[])
{
//Scanner class object created
Scanner sc=new Scanner(System.in);
//value of millimeter declared
double millimeter = 1;
//value of kilometer declared
double kilometer = 1;

//converting kilometer to millimeter
double mm = kilometer*1000000;
//converting millimeter to kilometer
double km = millimeter/1000000;
//printing result
System.out.println("Value of "+millimeter+" millimeter in kilometer: "+ km);
System.out.println("Value of "+kilometer+" kilometer in millimeter: "+ mm);
}
}
Output:

Value of 1.0 millimeter in kilometer: 1.0E-6
Value of 1.0 kilometer in millimeter: 1000000.0

### Method-2: Java Program to Convert Kilometer to Millimeter and Millimeter to Kilometer By Using User Input Value

Approach:

• Take user input of Kilometer and Millimeter value.
• Then convert Kilometer to Millimeter and Millimeter to Kilometer by using the formula.
• Print result.

Program:

import java.util.*;
public class Main
{
public static void main(String args[])
{
//Scanner class object created
Scanner sc=new Scanner(System.in);
//Taking the value input of double variable millimeter
System.out.println("Enter value of millimeter: ");
double millimeter = sc.nextDouble();
//Taking the value input of double variable kilometer
System.out.println("Enter value of kilometer: ");
double kilometer = sc.nextDouble();

//converting kilometer to millimeter
double mm = kilometer*1000000;
//converting millimeter to kilometer
double km = millimeter/1000000;
//printing result
System.out.println("Value of "+millimeter+" millimeter in kilometer: "+ km);
System.out.println("Value of "+kilometer+" kilometer in millimeter: "+ mm);
}
}
Output:

Enter value of millimeter:
88880000
Enter value of kilometer:
567
Value of 8.888E7 millimeter in kilometer: 88.88
Value of 567.0 kilometer in millimeter: 5.67E8


### Method-3: Java Program to Convert Kilometer to Millimeter and Millimeter to Kilometer By Using User Defined Method

Approach:

• Take user input of Kilometer and Millimeter value.
• Call a user defined method by passing Kilometer and Millimeter value as parameter.
• Inside method convert Kilometer to Millimeter and Millimeter to Kilometer by using the formula.
• Print result.

Program:

import java.util.*;
public class Main
{
public static void main(String args[])
{
//Scanner class object created
Scanner sc=new Scanner(System.in);
//Taking the value input of double variable millimeter
System.out.println("Enter value of millimeter: ");
double millimeter = sc.nextDouble();
//Taking the value input of double variable kilometer
System.out.println("Enter value of kilometer: ");
double kilometer = sc.nextDouble();
//calling user defined method convert()
convert(millimeter, kilometer);
}

//convert() method to convert millimeter to kilometer and vice versa
public static void convert(double millimeter, double kilometer)
{
//converting kilometer to millimeter
double mm = kilometer*1000000;
//converting millimeter to kilometer
double km = millimeter/1000000;
//printing result
System.out.println("Value of "+millimeter+" millimeter in kilometer: "+ km);
System.out.println("Value of "+kilometer+" kilometer in millimeter: "+ mm);
}
}
Output:

Enter value of millimeter:
9000500
Enter value of kilometer:
4.5
Value of 9000500.0 millimeter in kilometer: 9.0005
Value of 4.5 kilometer in millimeter: 4500000.0


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