---
title: significandWidth
framework: swift
role: symbol
role_heading: Instance Property
path: swift/float16/significandwidth
---

# significandWidth

The number of bits required to represent the value’s significand.

## Declaration

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

## Discussion

Discussion If this value is a finite nonzero number, significandWidth is the number of fractional bits required to represent the value of significand; otherwise, significandWidth is -1. The value of significandWidth is always -1 or between zero and significandBitCount. For example: For any representable power of two, significandWidth is zero, because significand is 1.0. If x is 10, x.significand is 1.01 in binary, so x.significandWidth is 2. If x is Float.pi, x.significand is 1.10010010000111111011011 in binary, and x.significandWidth is 23.