diff --git a/src/case.c b/src/case.c
index 9ab0223a..0ea48143 100644
--- a/src/case.c
+++ b/src/case.c
@@ -2664,7 +2664,7 @@ static const struct case_conversion_entry case_conversion_data[] =
 codepoint_t ucd_toupper(codepoint_t c)
 {
 	int begin = 0;
-	int end   = sizeof(case_conversion_data)/sizeof(case_conversion_data[0]);
+	int end   = (sizeof(case_conversion_data)/sizeof(case_conversion_data[0])) - 1;
 	while (begin <= end)
 	{
 		int pos = (begin + end) / 2;
@@ -2682,7 +2682,7 @@ codepoint_t ucd_toupper(codepoint_t c)
 codepoint_t ucd_tolower(codepoint_t c)
 {
 	int begin = 0;
-	int end   = sizeof(case_conversion_data)/sizeof(case_conversion_data[0]);
+	int end   = (sizeof(case_conversion_data)/sizeof(case_conversion_data[0])) - 1;
 	while (begin <= end)
 	{
 		int pos = (begin + end) / 2;
@@ -2700,7 +2700,7 @@ codepoint_t ucd_tolower(codepoint_t c)
 codepoint_t ucd_totitle(codepoint_t c)
 {
 	int begin = 0;
-	int end   = sizeof(case_conversion_data)/sizeof(case_conversion_data[0]);
+	int end   = (sizeof(case_conversion_data)/sizeof(case_conversion_data[0])) - 1;
 	while (begin <= end)
 	{
 		int pos = (begin + end) / 2;