diff --git a/toonz/sources/tnztools/irontool.cpp b/toonz/sources/tnztools/irontool.cpp
index a52b1f58..cff1e170 100644
--- a/toonz/sources/tnztools/irontool.cpp
+++ b/toonz/sources/tnztools/irontool.cpp
@@ -31,11 +31,11 @@ const int MY_ERROR = -1;
 //-----------------------------------------------------------------------------
 
 // index must be between 0 and controlPointCount-1
-inline bool isIncluded(int index, int left, int rigth) {
-  if (left < rigth) {
-    return left <= index && index <= rigth;
+inline bool isIncluded(int index, int left, int right) {
+  if (left < right) {
+    return left <= index && index <= right;
   } else {
-    return left <= index || index <= rigth;
+    return left <= index || index <= right;
   }
 }