diff --git a/pkg/registry/core/service/allocator/utils.go b/pkg/registry/core/service/allocator/utils.go
index baf64506e09..c034f51e6c9 100644
--- a/pkg/registry/core/service/allocator/utils.go
+++ b/pkg/registry/core/service/allocator/utils.go
@@ -24,8 +24,8 @@ import (
 // countBits returns the number of set bits in n
 func countBits(n *big.Int) int {
 	var count int = 0
-	for _, b := range n.Bytes() {
-		count += bits.OnesCount8(uint8(b))
+	for _, w := range n.Bits() {
+		count += bits.OnesCount64(uint64(w))
 	}
 	return count
 }