# Math.Round Method (Double, Int32)

.NET Framework 4.5

Rounds a double-precision floating-point value to a specified number of fractional digits.

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

## Syntax

```public static double Round(
double value,
int digits
)
```

#### 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.

#### Return Value

Type: System.Double
The number nearest to value that contains a number of fractional digits equal to digits.

## Exceptions

ExceptionCondition
ArgumentOutOfRangeException

digits is less than 0 or greater than 15.

## Remarks

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) method may not appear to round midpoint values to the nearest even value in the digits decimal position. 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.

```using System;

public class Example
{
public static void Main()
{
double[] values = { 2.125, 2.135, 2.145, 3.125, 3.135, 3.145 };
foreach (double value in values)
Console.WriteLine("{0} --> {1}", value, Math.Round(value, 2));

}
}
// The example displays the following output:
//       2.125 --> 2.12
//       2.135 --> 2.13
//       2.145 --> 2.14
//       3.125 --> 3.12
//       3.135 --> 3.14
//       3.145 --> 3.14
```

## Version Information

#### .NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

#### .NET Framework Client Profile

Supported in: 4, 3.5 SP1

#### Portable Class Library

Supported in: Portable Class Library

#### .NET for Windows Store apps

Supported in: Windows 8
Supported in: Windows Phone 8.1
Supported in: Windows Phone Silverlight 8.1
Supported in: Windows Phone Silverlight 8

## Platforms

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.