---
title: exponent
framework: swift
role: symbol
role_heading: Instance Property
path: swift/float80/exponent-swift.property
---

# exponent

The exponent of the floating-point value.

## Declaration

```swift
var exponent: Int { get }
```

## Discussion

Discussion The exponent of a floating-point value is the integer part of the logarithm of the value’s magnitude. For a value x of a floating-point type F, the magnitude can be calculated as the following, where ** is exponentiation: x.significand * (F.radix ** x.exponent) In the next example, y has a value of 21.5, which is encoded as 1.34375 * 2 ** 4. The significand of y is therefore 1.34375. let y: Double = 21.5 // y.significand == 1.34375 // y.exponent == 4 // Double.radix == 2 The exponent property has the following edge cases: If x is zero, then x.exponent is Int.min. If x is +/-infinity or NaN, then x.exponent is Int.max This property implements the logB operation defined by the IEEE 754 specification.