---
title: FloatingPointRoundingRule.down
framework: swift
role: symbol
role_heading: Case
path: swift/floatingpointroundingrule/down
---

# FloatingPointRoundingRule.down

Round to the closest allowed value that is less than or equal to the source.

## Declaration

```swift
case down
```

## Discussion

Discussion The following example shows the results of rounding numbers using this rule: (5.2).rounded(.down) // 5.0 (5.5).rounded(.down) // 5.0 (-5.2).rounded(.down) // -6.0 (-5.5).rounded(.down) // -6.0 This rule is equivalent to the C floor function and implements the roundToIntegralTowardNegative operation defined by the IEEE 754 specification.