diff --git a/src/gx/Font.cpp b/src/gx/Font.cpp
index 5767a44..948aacb 100644
--- a/src/gx/Font.cpp
+++ b/src/gx/Font.cpp
@@ -925,7 +925,7 @@ uint32_t TextBlockGetMaxCharsWithinWidthAndHeight(HTEXTFONT fontHandle, const ch
         lineBytes,
         DDCToNDCWidth(a7),
         scale,
-        DDCToNDCWidth(a9),
+        DDCToNDCHeight(a9),
         ConvertStringFlags(flags)
     );
 }