> For the complete documentation index, see [llms.txt](https://gold.gitbook.io/kotlin/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://gold.gitbook.io/kotlin/collections/aggregate-operations/sum.md).

# sum

```kotlin
public fun Iterable<Int>.sum(): Int {
    var sum: Int = 0
    for (element in this) {
        sum += element
    }
    return sum
}


val list = listOf(1, 2, 3, 4, 5)
println(list.sum())  // 15
```