Java – How to convert System.nanoTime to Seconds

By mkyong | Updated: December 6, 2018

Viewed: 18,456 (+150 pv/w)

Tags: elapsed time java time timeunit

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