Java How to convert System.nanoTime to Seconds

We can just divide the nanoTime by 1_000_000_000, or use the TimeUnit.SECONDS.convert to convert it.

package com.mkyong;
import java.util.concurrent.TimeUnit;
public class JavaExample {
    public static void main(String[] args) throws InterruptedException {
        long start = System.nanoTime();
        Thread.sleep(5000);
        long end = System.nanoTime();
        long elapsedTime = end - start;
        System.out.println(elapsedTime);
        // 1 second = 1_000_000_000 nano seconds
        double elapsedTimeInSecond = (double) elapsedTime / 1_000_000_000;
        System.out.println(elapsedTimeInSecond + " seconds");
        // TimeUnit
        long convert = TimeUnit.SECONDS.convert(elapsedTime, TimeUnit.NANOSECONDS);
        System.out.println(convert + " seconds");

Output

5000353564
5.000353564 seconds
5 seconds

References

1. Wikipedia – Nanosecond
2. TimeUnit Javadoc