# Math.Round Method (Double, Int32, MidpointRounding)

.NET Framework (current version)

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Rounds a double-precision floating-point value to a specified number of fractional digits. A parameter specifies how to round the value if it is midway between two numbers.

Namespace:   System
Assembly:  mscorlib (in mscorlib.dll)

## Syntax

```Public Shared Function Round (
value As Double,
digits As Integer,
mode As MidpointRounding
) As Double
```

#### Parameters

value
Type: System.Double

A double-precision floating-point number to be rounded.

digits
Type: System.Int32

The number of fractional digits in the return value.

mode
Type: System.MidpointRounding

Specification for how to round value if it is midway between two other numbers.

#### Return Value

Type: System.Double

The number nearest to value that has a number of fractional digits equal to digits. If value has fewer fractional digits than digits, value is returned unchanged.

## Exceptions

Exception Condition
ArgumentOutOfRangeException

digits is less than 0 or greater than 15.

ArgumentException

mode is not a valid value of System.MidpointRounding.

Note

## Notes to Callers:

Because of the loss of precision that can result from representing decimal values as floating-point numbers or performing arithmetic operations on floating-point values, in some cases the Round(Double, Int32, MidpointRounding) method may not appear to round midpoint values as specified by the mode parameter. This is illustrated in the following example, where 2.135 is rounded to 2.13 instead of 2.14. This occurs because internally the method multiplies value by 10digits, and the multiplication operation in this case suffers from a loss of precision.

```Module Example
Public Sub Main()
Dim values() As Double = { 2.125, 2.135, 2.145, 3.125, 3.135, 3.145 }
For Each value As Double In values
Console.WriteLine("{0} --> {1}", value,
Math.Round(value, 2, MidpointRounding.AwayFromZero))
Next
End Sub
End Module
' The example displays the following output:
'       2.125 --> 2.13
'       2.135 --> 2.13
'       2.145 --> 2.15
'       3.125 --> 3.13
'       3.135 --> 3.14
'       3.145 --> 3.15
```

## Version Information

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1