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# Math.Round Method (Double)

.NET Framework 4.6 and 4.5

Rounds a double-precision floating-point value to the nearest integral value.

Namespace:  System
Assemblies:   mscorlib (in mscorlib.dll)
System.Runtime.Extensions (in System.Runtime.Extensions.dll)

## Syntax

```public static double Round(
double a
)
```

#### Parameters

a
Type: System.Double

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

#### Return Value

Type: System.Double
The integer nearest a. If the fractional component of a is halfway between two integers, one of which is even and the other odd, then the even number is returned. Note that this method returns a Double instead of an integral type.

## 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) method may not appear to round midpoint values to the nearest even integer. In the following example, because the floating-point value .1 has no finite binary representation, the first call to the Round(Double) method with a value of 11.5 returns 11 instead of 12.

```using System;

public class Example
{
public static void Main()
{
double value = 11.1;
for (int ctr = 0; ctr <= 5; ctr++)

Console.WriteLine();

value = 11.5;
}

{
Console.WriteLine("{0} --> {1}", value, Math.Round(value));
return value + .1;
}
}
// The example displays the following output:
//       11.1 --> 11
//       11.2 --> 11
//       11.3 --> 11
//       11.4 --> 11
//       11.5 --> 11
//       11.6 --> 12
//
//       11.5 --> 12
```

## Version Information

#### .NET Framework

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

#### .NET Framework Client Profile

Supported in: 4, 3.5 SP1

#### XNA Framework

Supported in: 3.0, 2.0, 1.0

#### .NET for Windows Phone apps

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

#### Portable Class Library

Supported in: Portable Class Library