Learn to **round off numeric values (floats and doubles) to 2 decimal places in Java**. Note that we can use the given solutions to round off to any number of places according to requirements.

```
double number = 4.56789;
// 1. Using Math.round()
double rounded = Math.round(number * 100.0) / 100.0; // 4.57
// 2. Using BigDecimal
BigDecimal rounded = new BigDecimal(number).setScale(2, RoundingMode.HALF_UP); // 4.57
// 3. Using Apache Commons Math's Precision Class
float rounded = Precision.round(number, 2, RoundingMode.ROUND_HALF_EVEN.ordinal()); // 4.57
// 4. Displaying a rounded off value
DecimalFormat df = new DecimalFormat("###.##");
String rounded = df.format(number); //4.57
```

*BigDecimal* Class

1. Using **Using BigDecimal class is the recommended approach** for doing numerical operations in Java.

*BigDecimal*is an immutable class and provides operations for arithmetic, scale manipulation, rounding, comparison, hashing, and format conversion.

The `BigDecimal.setScale()`

method takes two arguments. The first is *scale* i.e. number of places to round off. The second is the rounding mode. Different rounding modes can give different results so test them out before finalizing.

The ** java.math.RoundingMode.HALF_EVEN is the recommended mode in most cases**. This mode rounds towards the “nearest neighbor” unless both neighbors are equidistant, in which case, round towards the even neighbor. It is sometimes known as “

**” and is mainly used in the USA. This mode corresponds to the IEEE 754-2019 rounding-direction attribute**

*Banker’s rounding**roundTiesToEven*.

```
float number = 123.456f;
BigDecimal bd = new BigDecimal(number);
BigDecimal roundedOffBd = bd.setScale(2, java.math.RoundingMode.HALF_EVEN);
System.out.println(roundedOffBd); //123.46
```

*Precision* class

2. Using Commons Math’s Similar to *BigDecimal*, we can use the rounding mode *HALF_EVEN* (or any other required mode) with the *Precision* class provided by Apache’s commons-math3 library.

The *Precision.round(scale, mode)* provides a clean method that is also easy to read.

```
float number = 123.456f;
float roundedOffNumber = Precision.round(number, 2, RoundingMode.ROUND_HALF_EVEN.ordinal());
System.out.println(roundedOffNumber); //123.45
```

*Math.round()* and Division

3. Using This solution does not provide the control of the rounding mode and always rounds off to mode *HALF_UP*. This may be useful in some situations **for non-sensitive calculations** where accuracy is not of that importance.

```
float number = 123.456f;
System.out.println(roundUp(number, 2)); //123.46
public static double roundUp(double value, int places) {
double scale = Math.pow(10, places);
return Math.round(value * scale) / scale;
}
```

*DecimalFormat*

4. Displaying Rounded Off Value using If we only need to display the rounded-off value of a numeric number, we can use `DecimalFormat`

class and use its `format("###.##")`

method for it.

```
float number = 123.456f;
DecimalFormat df = new DecimalFormat("###.##");
System.out.println(df.format(number)); //123.46
```

## 5. Conclusion

This Java tutorial taught us to round off a given floating point number to 2 decimal points using different techniques. We learned to use the Decimal class (*recommended*), *Math*, *Precision* and *DecimalFormat* classes. As a best practice, always use the *Decimal* class with rounding mode set to *HALF_EVEN*.

Happy Learning !!

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