diff --git a/icu4c/source/i18n/anytrans.cpp b/icu4c/source/i18n/anytrans.cpp
index 45e97e44755..d46668ec910 100644
--- a/icu4c/source/i18n/anytrans.cpp
+++ b/icu4c/source/i18n/anytrans.cpp
@@ -309,7 +309,7 @@ static UScriptCode scriptNameToCode(const UnicodeString& name) {
     UBool isInvariant = uprv_isInvariantUString(name.getBuffer(), nameLen);
     
     if (isInvariant) {
-        name.extract(0, nameLen, buf, sizeof(buf), US_INV);
+        name.extract(0, nameLen, buf, (int32_t)sizeof(buf), US_INV);
         buf[127] = 0;   // Make sure that we NULL terminate the string.
     }
     if (!isInvariant || uscript_getCode(buf, &code, 1, &ec) != 1 || U_FAILURE(ec))
diff --git a/icu4c/source/i18n/translit.cpp b/icu4c/source/i18n/translit.cpp
index 61b7283a4f6..fb7322178d5 100644
--- a/icu4c/source/i18n/translit.cpp
+++ b/icu4c/source/i18n/translit.cpp
@@ -790,7 +790,7 @@ UnicodeString& U_EXPORT2 Transliterator::getDisplayName(const UnicodeString& id,
                 uprv_strcpy(key, RB_SCRIPT_DISPLAY_NAME_PREFIX);
                 args[j].getString(s);
                 if (uprv_isInvariantUString(s.getBuffer(), s.length())) {
-                    s.extract(0, sizeof(key)-length-1, key+length, sizeof(key)-length-1, US_INV);
+                    s.extract(0, sizeof(key)-length-1, key+length, (int32_t)sizeof(key)-length-1, US_INV);
 
                     resString = bundle.getStringEx(key, status);