Collapse the table of content
Expand the table of content
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here. ArchiveDisclaimer

float (C# Reference)

The float keyword denotes a simple type that stores 32-bit floating-point values. The following table shows the precision and approximate range for the float type.

Type Approximate range Precision .NET Framework type


±1.5 × 10−45 to ±3.4 × 1038

7 digits


By default, a real numeric literal on the right-hand side of the assignment operator is treated as double. Therefore, to initialize a float variable, use the suffix f or F, like this:

        float x = 3.5F;

If you do not use the suffix in the previous declaration, you will get a compilation error because you are attempting to store a double value into a float variable.

You can mix numeric integral types and floating-point types in an expression. In this case, the integral types are converted to floating-point types. The evaluation of the expression is performed according to the following rules:

  • If one of the floating-point types is double, the expression evaluates to double or bool in the case of relational or Boolean expressions.

  • If there is no double type in the expression, the expression evaluates to float or bool in the case of relational or Boolean expressions.

A floating-point expression can contain the following sets of values:

  • Positive and negative zero

  • Positive and negative infinity

  • Not-a-Number value (NaN)

  • The finite set of nonzero values

For more information on these values, refer to IEEE Standard for Binary Floating-Point Arithmetic, available on the Web site http://www.ieee.org/.

In the following example, an int, a short, and a float are included in a mathematical expression giving a float result. Notice that there is no double in the expression.

// keyword_float.cs
// Mixing types in expressions
using System;
class MixedTypes 
    static void Main() 
        int x = 3;
        float y = 4.5f;
        short z = 5;
        Console.WriteLine("The result is {0}", x * y / z); 

The result is 2.7

For more information, see the following sections in the C# Language Specification:

  • 4.1.6 Floating Point Types

  • 6.2.1 Explicit Numeric Conversions

© 2016 Microsoft