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
	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 abstract int 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[]