diff --git a/fpdfsdk/include/fpdf_ext.h b/fpdfsdk/include/fpdf_ext.h
index 5efe0e6..96e3c85 100644
--- a/fpdfsdk/include/fpdf_ext.h
+++ b/fpdfsdk/include/fpdf_ext.h
@@ -71,7 +71,7 @@
 //flags for page mode. 
 
 //Unknown value
-#define PAGEMODE_UNKONOWN		-1
+#define PAGEMODE_UNKNOWN		-1
 
 //Neither document outline nor thumbnail images visible
 #define PAGEMODE_USENONE		0
diff --git a/fpdfsdk/src/fpdf_ext.cpp b/fpdfsdk/src/fpdf_ext.cpp
index 2d9e5ae..916cb20 100644
--- a/fpdfsdk/src/fpdf_ext.cpp
+++ b/fpdfsdk/src/fpdf_ext.cpp
@@ -219,10 +219,10 @@
 
 DLLEXPORT int FPDFDoc_GetPageMode(FPDF_DOCUMENT document)
 {
-	if (!document) return PAGEMODE_UNKONOWN;
+	if (!document) return PAGEMODE_UNKNOWN;
 	CPDF_Dictionary *pRoot = ((CPDF_Document*)document)->GetRoot();
 	if (!pRoot)
-		return PAGEMODE_UNKONOWN;
+		return PAGEMODE_UNKNOWN;
 	CPDF_Object* pName = pRoot->GetElement("PageMode");
 	if (!pName)
 		return PAGEMODE_USENONE;
@@ -241,5 +241,5 @@
 	else if (strPageMode.EqualNoCase(FX_BSTR("UseAttachments")))
 		return PAGEMODE_USEATTACHMENTS;
 
-	return PAGEMODE_UNKONOWN;
+	return PAGEMODE_UNKNOWN;
 }