What Is BigDecimal Data Type in Java?


Heather Bennett

The BigDecimal data type in Java is a class that provides a way to perform precise decimal arithmetic. It is particularly useful when dealing with financial and monetary calculations where accuracy is crucial.

Why Use BigDecimal?

When performing arithmetic operations on floating-point numbers, you may encounter rounding errors due to the limited precision of the float and double data types. These errors can accumulate and lead to incorrect results, especially in financial calculations.

To overcome this limitation, Java provides the BigDecimal class, which allows you to perform arithmetic operations with arbitrary precision.

Create a BigDecimal Object

To create a BigDecimal object, you can use one of its constructors:

  • BigDecimal(String val): Creates a new BigDecimal object from a string representation of a number.
  • BigDecimal(double val): Creates a new BigDecimal object from a double value.
  • BigDecimal(BigInteger val): Creates a new BigDecimal object from a BigInteger value.

Precision and Scale

The precision of a BigDecimal object refers to the total number of digits it can represent. The scale represents the number of digits after the decimal point.

Precision Example:

If we have the number 123.45, its precision would be 5 because it has five digits in total: 1, 2, 3, 4, and 5.

Scale Example:

If we have the number 123.45, its scale would be 2 because it has two digits after the decimal point: 4 and 5.

Performing Arithmetic Operations

The BigDecimal class provides methods to perform arithmetic operations such as addition, subtraction, multiplication, and division. These operations can be performed on two BigDecimal objects or between a BigDecimal object and a primitive data type (e.g., int, long).

Addition Example:

BigDecimal num1 = new BigDecimal("10.50");
BigDecimal num2 = new BigDecimal("5.25");

BigDecimal sum = num1.add(num2);

System.out.println(sum); // Output: 15.75

Multiplication Example:

BigDecimal num1 = new BigDecimal("10");
int num2 = 5;

BigDecimal product = num1.multiply(new BigDecimal(num2));

System.println(product); // Output: 50

Rounding and Comparison

The BigDecimal class also provides methods for rounding numbers and comparing them with other BigDecimal objects.

Rounding Example:

BigDecimal number = new BigDecimal("10.555");

// Round to two decimal places
number = number.setScale(2, RoundingMode.HALF_UP);

System.println(number); // Output: 10.56

Comparison Example:

BigDecimal num1 = new BigDecimal("10");
BigDecimal num2 = new BigDecimal("5");

int comparisonResult = num1.compareTo(num2);

if (comparisonResult == 0) {
    System.println("Both numbers are equal. ");
} else if (comparisonResult > 0) {
    System.println("num1 is greater than num2. 

} else {
    System.println("num1 is less than num2. ");


The BigDecimal data type in Java provides a reliable way to perform precise decimal arithmetic. It ensures accuracy in financial calculations and other scenarios where precision is paramount. By using the BigDecimal class, you can avoid rounding errors and produce correct results.

Remember to always use the appropriate constructors and methods to create and manipulate BigDecimal objects based on your specific requirements.

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