diff --git a/libs/main/text/pistring.cpp b/libs/main/text/pistring.cpp
index 534bc955..db3b9da8 100644
--- a/libs/main/text/pistring.cpp
+++ b/libs/main/text/pistring.cpp
@@ -469,7 +469,7 @@ void PIString::buildData(const char * cp) const {
 	UErrorCode e((UErrorCode)0);
 	UConverter * cc = ucnv_open(cp, &e);
 	if (cc) {
-		const size_t len = MB_CUR_MAX * size() + 1;
+		const size_t len = UCNV_GET_MAX_BYTES_FOR_STRING(size(), ucnv_getMaxCharSize(cc)) + 1; // MB_CUR_MAX * size() + 1;
 		data_            = (char *)malloc(len);
 		int sz           = ucnv_fromUChars(cc, data_, len, (const UChar *)(d.data()), d.size_s(), &e);
 		ucnv_close(cc);