diff --git a/plus_one/plus_one.go b/plus_one/plus_one.go
index ab91ce3..b9711b7 100644
--- a/plus_one/plus_one.go
+++ b/plus_one/plus_one.go
@@ -2,7 +2,7 @@ package plus_one
 
 func plusOne(digits []int) []int {
 	carry := 1
-	for i := len(digits); i >= 0; i++ {
+	for i := len(digits)-1; i >= 0; i-- {
 		sum := carry + digits[i]
 		if sum < 10 {
 			digits[i] = sum