diff --git a/include/fmt/format.h b/include/fmt/format.h
index 43403027ba1c..fdb2cf442a4c 100644
--- a/include/fmt/format.h
+++ b/include/fmt/format.h
@@ -1523,7 +1523,7 @@ auto find_escape(const Char* begin, const Char* end)
     -> find_escape_result<Char> {
   for (; begin != end; ++begin) {
     uint32_t cp = static_cast<make_unsigned_char<Char>>(*begin);
-    if (sizeof(Char) == 1 && cp >= 0x80) continue;
+    if (const_check(sizeof(Char) == 1) && cp >= 0x80) continue;
     if (needs_escape(cp)) return {begin, begin + 1, cp};
   }
   return {begin, nullptr, 0};