diff --git a/Source/GSFormat.m b/Source/GSFormat.m
index 38636cd27..3c8a0a664 100644
--- a/Source/GSFormat.m
+++ b/Source/GSFormat.m
@@ -1772,7 +1772,7 @@ NSDictionary *locale)
 		     * precision required for output.
 		     */
                     len = 0;
-                    while (len < prec && str[0] != 0)
+                    while (len < prec && str[len] != 0)
                       {
                         len++;
 		      }
@@ -1787,7 +1787,7 @@ NSDictionary *locale)
                      * to check and emulate OSX behavior.
                      */
                     len = 0;
-                    while (len < prec && str[0] != 0)
+                    while (len < prec && str[len] != 0)
                       {
                         len++;
 		      }