diff --git a/src/checkstyle/com/puppycrawl/tools/checkstyle/api/Utils.java b/src/checkstyle/com/puppycrawl/tools/checkstyle/api/Utils.java
index 6472174dd..0c0d439e7 100644
--- a/src/checkstyle/com/puppycrawl/tools/checkstyle/api/Utils.java
+++ b/src/checkstyle/com/puppycrawl/tools/checkstyle/api/Utils.java
@@ -101,8 +101,9 @@ public final class Utils
                                          int aTabWidth)
     {
         int len = 0;
+        final char[] chars = aString.toCharArray();
         for (int idx = 0; idx < aToIdx; idx++) {
-            if (aString.charAt(idx) == '\t') {
+            if (chars[idx] == '\t') {
                 len = (len / aTabWidth + 1) * aTabWidth;
             }
             else {