Added in API level 1

Summary: Enums | Methods | Inherited Methods

RoundingMode

public final enum RoundingMode
extends Enum<RoundingMode>

java.lang.Object
↳	java.lang.Enum<java.math.RoundingMode>
	↳	java.math.RoundingMode

Specifies a rounding policy for numerical operations capable of discarding precision. Each rounding mode indicates how the least significant returned digit of a rounded result is to be calculated. If fewer digits are returned than the digits needed to represent the exact numerical result, the discarded digits will be referred to as the discarded fraction regardless the digits' contribution to the value of the number. In other words, considered as a numerical value, the discarded fraction could have an absolute value greater than one.

Each rounding mode description includes a table listing how different two-digit decimal values would round to a one digit decimal value under the rounding mode in question. The result column in the tables could be gotten by creating a BigDecimal number with the specified value, forming a MathContext object with the proper settings (precision set to 1, and the roundingMode set to the rounding mode in question), and calling round on this number with the proper MathContext. A summary table showing the results of these rounding operations for all rounding modes appears below.

**Summary of Rounding Operations Under Different Rounding Modes**
Input Number	Result of rounding input to one digit with the given rounding mode
Input Number	`UP`	`DOWN`	`CEILING`	`FLOOR`	`HALF_UP`	`HALF_DOWN`	`HALF_EVEN`	`UNNECESSARY`
5.5	6	5	6	5	6	5	6	throw `ArithmeticException`
2.5	3	2	3	2	3	2	2	throw `ArithmeticException`
1.6	2	1	2	1	2	2	2	throw `ArithmeticException`
1.1	2	1	2	1	1	1	1	throw `ArithmeticException`
1.0	1	1	1	1	1	1	1	1
-1.0	-1	-1	-1	-1	-1	-1	-1	-1
-1.1	-2	-1	-1	-2	-1	-1	-1	throw `ArithmeticException`
-1.6	-2	-1	-1	-2	-2	-2	-2	throw `ArithmeticException`
-2.5	-3	-2	-2	-3	-3	-2	-2	throw `ArithmeticException`
-5.5	-6	-5	-5	-6	-6	-5	-6	throw `ArithmeticException`

This enum is intended to replace the integer-based enumeration of rounding mode constants in BigDecimal (BigDecimal#ROUND_UP, BigDecimal#ROUND_DOWN, etc. ).

See also:

BigDecimal
MathContext

Summary

Enum values
`RoundingMode`	`CEILING` Rounding mode to round towards positive infinity.
`RoundingMode`	`DOWN` Rounding mode to round towards zero.
`RoundingMode`	`FLOOR` Rounding mode to round towards negative infinity.
`RoundingMode`	`HALF_DOWN` Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down.
`RoundingMode`	`HALF_EVEN` Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor.
`RoundingMode`	`HALF_UP` Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up.
`RoundingMode`	`UNNECESSARY` Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary.
`RoundingMode`	`UP` Rounding mode to round away from zero.

Public methods
`static RoundingMode`	`valueOf(String name)`
`static RoundingMode`	`valueOf(int rm)` Returns the `RoundingMode` object corresponding to a legacy integer rounding mode constant in `BigDecimal`.
`static final RoundingMode[]`	`values()`

Inherited methods

From class


        
          java.lang.Enum

`final Object`	`clone()` Throws CloneNotSupportedException.
`final int`	`compareTo(RoundingMode o)` Compares this enum with the specified object for order.
`final boolean`	`equals(Object other)` Returns true if the specified object is equal to this enum constant.
`final void`	`finalize()` enum classes cannot have finalize methods.
`final Class<RoundingMode>`	`getDeclaringClass()` Returns the Class object corresponding to this enum constant's enum type.
`final int`	`hashCode()` Returns a hash code for this enum constant.
`final String`	`name()` Returns the name of this enum constant, exactly as declared in its enum declaration.
`final int`	`ordinal()` Returns the ordinal of this enumeration constant (its position in its enum declaration, where the initial constant is assigned an ordinal of zero).
`String`	`toString()` Returns the name of this enum constant, as contained in the declaration.
`static <T extends Enum<T>> T`	`valueOf(Class<T> enumClass, String name)` Returns the enum constant of the specified enum class with the specified name.

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface


        
          java.lang.Comparable


      compareTo(RoundingMode o)

Compares this object with the specified object for order.

Enum values

CEILING

Added in API level 1

public static final RoundingMode CEILING

Rounding mode to round towards positive infinity. If the result is positive, behaves as for RoundingMode.UP; if negative, behaves as for RoundingMode.DOWN. Note that this rounding mode never decreases the calculated value. This mode corresponds to the IEEE 754-2019 rounding-direction attribute roundTowardPositive.

Example:

Rounding mode CEILING Examples
Input Number	Input rounded to one digit with `CEILING` rounding
5.5	6
2.5	3
1.6	2
1.1	2
1.0	1
-1.0	-1
-1.1	-1
-1.6	-1
-2.5	-2
-5.5	-5

DOWN

Added in API level 1

public static final RoundingMode DOWN

Rounding mode to round towards zero. Never increments the digit prior to a discarded fraction (i.e., truncates). Note that this rounding mode never increases the magnitude of the calculated value. This mode corresponds to the IEEE 754-2019 rounding-direction attribute roundTowardZero.

Example:

Rounding mode DOWN Examples
Input Number	Input rounded to one digit with `DOWN` rounding
5.5	5
2.5	2
1.6	1
1.1	1
1.0	1
-1.0	-1
-1.1	-1
-1.6	-1
-2.5	-2
-5.5	-5

FLOOR

Added in API level 1

public static final RoundingMode FLOOR

Rounding mode to round towards negative infinity. If the result is positive, behave as for RoundingMode.DOWN; if negative, behave as for RoundingMode.UP. Note that this rounding mode never increases the calculated value. This mode corresponds to the IEEE 754-2019 rounding-direction attribute roundTowardNegative.

Example:

Rounding mode FLOOR Examples
Input Number	Input rounded to one digit with `FLOOR` rounding
5.5	5
2.5	2
1.6	1
1.1	1
1.0	1
-1.0	-1
-1.1	-2
-1.6	-2
-2.5	-3
-5.5	-6

HALF_DOWN

Added in API level 1

public static final RoundingMode HALF_DOWN

Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round down. Behaves as for RoundingMode.UP if the discarded fraction is > 0.5; otherwise, behaves as for RoundingMode.DOWN.

Example:

Rounding mode HALF_DOWN Examples
Input Number	Input rounded to one digit with `HALF_DOWN` rounding
5.5	5
2.5	2
1.6	2
1.1	1
1.0	1
-1.0	-1
-1.1	-1
-1.6	-2
-2.5	-2
-5.5	-5

HALF_EVEN

Added in API level 1

public static final RoundingMode HALF_EVEN

Rounding mode to round towards the "nearest neighbor" unless both neighbors are equidistant, in which case, round towards the even neighbor. Behaves as for RoundingMode.HALF_UP if the digit to the left of the discarded fraction is odd; behaves as for RoundingMode.HALF_DOWN if it's even. Note that this is the rounding mode that statistically minimizes cumulative error when applied repeatedly over a sequence of calculations. It is sometimes known as "Banker's rounding," and is chiefly used in the USA. This rounding mode is analogous to the rounding policy used for float and double arithmetic in Java. This mode corresponds to the IEEE 754-2019 rounding-direction attribute roundTiesToEven.

Example:

Rounding mode HALF_EVEN Examples
Input Number	Input rounded to one digit with `HALF_EVEN` rounding
5.5	6
2.5	2
1.6	2
1.1	1
1.0	1
-1.0	-1
-1.1	-1
-1.6	-2
-2.5	-2
-5.5	-6

HALF_UP

Added in API level 1

public static final RoundingMode HALF_UP

Rounding mode to round towards "nearest neighbor" unless both neighbors are equidistant, in which case round up. Behaves as for RoundingMode.UP if the discarded fraction is ≥ 0.5; otherwise, behaves as for RoundingMode.DOWN. Note that this is the rounding mode commonly taught at school. This mode corresponds to the IEEE 754-2019 rounding-direction attribute roundTiesToAway.

Example:

Rounding mode HALF_UP Examples
Input Number	Input rounded to one digit with `HALF_UP` rounding
5.5	6
2.5	3
1.6	2
1.1	1
1.0	1
-1.0	-1
-1.1	-1
-1.6	-2
-2.5	-3
-5.5	-6

UNNECESSARY

Added in API level 1

public static final RoundingMode UNNECESSARY

Rounding mode to assert that the requested operation has an exact result, hence no rounding is necessary. If this rounding mode is specified on an operation that yields an inexact result, an ArithmeticException is thrown.

Example:

Rounding mode UNNECESSARY Examples
Input Number	Input rounded to one digit with `UNNECESSARY` rounding
5.5	throw `ArithmeticException`
2.5	throw `ArithmeticException`
1.6	throw `ArithmeticException`
1.1	throw `ArithmeticException`
1.0	1
-1.0	-1
-1.1	throw `ArithmeticException`
-1.6	throw `ArithmeticException`
-2.5	throw `ArithmeticException`
-5.5	throw `ArithmeticException`

UP

Added in API level 1

public static final RoundingMode UP

Rounding mode to round away from zero. Always increments the digit prior to a non-zero discarded fraction. Note that this rounding mode never decreases the magnitude of the calculated value.

Example:

Rounding mode UP Examples
Input Number	Input rounded to one digit with `UP` rounding
5.5	6
2.5	3
1.6	2
1.1	2
1.0	1
-1.0	-1
-1.1	-2
-1.6	-2
-2.5	-3
-5.5	-6

Public methods

valueOf

public static RoundingMode valueOf (String name)

Parameters
`name`	`String`

Returns
`RoundingMode`

valueOf

Added in API level 1

public static RoundingMode valueOf (int rm)

Returns the RoundingMode object corresponding to a legacy integer rounding mode constant in BigDecimal.

Parameters
`rm`	`int`: legacy integer rounding mode to convert

Returns
`RoundingMode`	`RoundingMode` corresponding to the given integer.

Throws
`IllegalArgumentException`	integer is out of range

values

public static final RoundingMode[] values ()

Returns
`RoundingMode[]`