java round double/float to 2 decimal places

In this post, we will see how to round double to 2 decimal places in java.
There are many ways to do it.Let’s go through few ways.
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Let’s understand each with the help of simple example.

Using DecimalFormat

You can use DecimalFormat too to round number to 2 decimal places.

package org.arpit.java2blog;

import java.text.DecimalFormat;

public class DecimalFormatMain {

    public static void main(String[] args) {
        double d=2343.5476;
        DecimalFormat df = new DecimalFormat("###.##");
        System.out.println("Rounded double (DecimalFormat) : " + df.format(d));
    }

}

Output:

Using BigDecimal

You can convert double or float to BigDecimal and use setScale() method to round double/float to 2 decimal places.
Here is the example:

package org.arpit.java2blog;

import java.math.BigDecimal;
import java.math.RoundingMode;

public class BigDecimalRoundDoubleMain {

    public static void main(String[] args) {
        double d = BigDecimalRoundDoubleMain.roundDouble(2343.5476, 2);
        System.out.println("Rounded Double: "+d);

        float f = BigDecimalRoundDoubleMain.roundFloat(2343.5476f, 2);
        System.out.println("Rounded Float: "+f);
    }

    private static double roundDouble(double d, int places) {

        BigDecimal bigDecimal = new BigDecimal(Double.toString(d));
        bigDecimal = bigDecimal.setScale(places, RoundingMode.HALF_UP);
        return bigDecimal.doubleValue();
    }

    private static float roundFloat(float f, int places) {

        BigDecimal bigDecimal = new BigDecimal(Float.toString(f));
        bigDecimal = bigDecimal.setScale(places, RoundingMode.HALF_UP);
        return bigDecimal.floatValue();
    }
}

Output:

Using Math.round(double*100.0)/100.0

package org.arpit.java2blog;

public class MathRoundMain {

    public static void main(String[] args) {

        double d=2343.5476;
        double roundedDouble = Math.round(d * 100.0) / 100.0;
        System.out.println("Rounded double: "+roundedDouble);

        float f=2343.5476f;
        float roundedFloat = (float)Math.round(f * 100.0) / 100.0;
        System.out.println("Rounded float: "+roundedFloat);
    }

}

Output:

You must be wondering how this works.

Using Apache common Math

You can also use Apache common‘s math library to round double or float to 2 decimal places.
Add the following dependency to pom.xml.

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-math3</artifactId>
    <version>3.6.1</version>
</dependency>

You can find versions of commons-math over here.
Here is the example:

package org.arpit.java2blog;

import org.apache.commons.math3.util.Precision;

public class ApacheMathDoubleMain {

    public static void main(String[] args) {
        double d=2343.5476;
        double roundedDouble = Precision.round(d,2);
        System.out.println("Rounded double: "+roundedDouble);

        float f=2343.5476f;
        float roundedFloat = Precision.round(f, 2);
        System.out.println("Rounded float: "+roundedFloat);
    }
}

That’s all about rounding double/float to 2 decimal places