Go Float Data Types

The float data types are used to store positive and negative numbers with a decimal point, like 35.3, -2.34, or 3597.34987.

The float data type has two keywords:

Type	Size	Range
`float32`	32 bits	-3.4e+38 to 3.4e+38.
`float64`	64 bits	-1.7e+308 to +1.7e+308.

Tip: The default type for float is float64. If you do not specify a type, the type will be float64.

The float32 Keyword

Example

This example shows how to declare some variables of type float32:

package main
import ("fmt")

func main() {
var x float32 = 123.78
var y float32 = 3.4e+38
fmt.Printf("Type: %T, value: %v\n", x, x)
fmt.Printf("Type: %T, value: %v", y, y)
}

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The float64 Keyword

The float64 data type can store a larger set of numbers than float32.

Example

This example shows how to declare a variable of type float64:

package main
import ("fmt")

func main() {
var x float64 = 1.7e+308
fmt.Printf("Type: %T, value: %v", x, x)
}

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Which Float Type to Use?

The type of float to choose, depends on the value the variable has to store.

Example

This example will result in an error because 3.4e+39 is out of range for float32:

package main
import ("fmt")

func main() {
var x float32= 3.4e+39
fmt.Println(x)
}

Result:


      ./prog.go:5:7: constant 3.4e+39 overflows float32

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