diff --git a/include/nlohmann/detail/input/binary_reader.hpp b/include/nlohmann/detail/input/binary_reader.hpp
index a3b95e9d6..f37f04a72 100644
--- a/include/nlohmann/detail/input/binary_reader.hpp
+++ b/include/nlohmann/detail/input/binary_reader.hpp
@@ -62,8 +62,8 @@ static inline bool little_endianness(int num = 1) noexcept
 /*!
 @brief deserialization of CBOR, MessagePack, and UBJSON values
 */
-template<typename BasicJsonType, typename InputAdapterType, typename Allocator = std::allocator<  BasicJsonType*>
-         , typename SAX = json_sax_dom_parser<BasicJsonType, Allocator>>
+template<typename BasicJsonType, typename InputAdapterType, typename AllocatorJson = std::allocator<  BasicJsonType*>, typename AllocatorChar = std::allocator< typename InputAdapterType::char_type>
+         , typename SAX = json_sax_dom_parser<BasicJsonType, AllocatorJson>>
 class binary_reader
 {
     using number_integer_t = typename BasicJsonType::number_integer_t;
@@ -2695,7 +2695,7 @@ class binary_reader
 
         // parse number string
         using ia_type = decltype(detail::input_adapter(number_vector));
-        auto number_lexer = detail::lexer<BasicJsonType, ia_type, Allocator>(detail::input_adapter(number_vector), false);
+        auto number_lexer = detail::lexer<BasicJsonType, ia_type, AllocatorChar>(detail::input_adapter(number_vector), false);
         const auto result_number = number_lexer.scan();
         const auto number_string = number_lexer.get_token_string();
         const auto result_remainder = number_lexer.scan();
@@ -3002,8 +3002,8 @@ class binary_reader
 };
 
 #ifndef JSON_HAS_CPP_17
-    template<typename BasicJsonType, typename InputAdapterType, typename Allocator, typename SAX>
-    constexpr std::size_t binary_reader<BasicJsonType, InputAdapterType, Allocator, SAX>::npos;
+    template<typename BasicJsonType, typename InputAdapterType, typename AllocatorJson, typename  AllocatorChar, typename SAX>
+    constexpr std::size_t binary_reader<BasicJsonType, InputAdapterType, AllocatorJson, AllocatorChar, SAX>::npos;
 #endif
 
 }  // namespace detail
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index b04e94206..6ffa8b867 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -112,7 +112,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     friend class ::nlohmann::detail::iter_impl;
     template<typename BasicJsonType, typename CharType>
     friend class ::nlohmann::detail::binary_writer;
-    template<typename BasicJsonType, typename InputType, typename Allocator, typename SAX>
+    template<typename BasicJsonType, typename InputType, typename AllocatorJson, typename AllocatorChar, typename SAX>
     friend class ::nlohmann::detail::binary_reader;
     template<typename BasicJsonType, typename Allocator>
     friend class ::nlohmann::detail::json_sax_dom_parser;
@@ -153,8 +153,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     template<typename CharType>
     using output_adapter_t = ::nlohmann::detail::output_adapter_t<CharType>;
 
-    template<typename InputType>
-    using binary_reader = ::nlohmann::detail::binary_reader<basic_json, InputType, AllocatorType<basic_json*>>;
+    template<typename InputType, typename CharType = char>
+    using binary_reader = ::nlohmann::detail::binary_reader<basic_json, InputType, AllocatorType<basic_json*>, AllocatorType<CharType>>;
     template<typename CharType> using binary_writer = ::nlohmann::detail::binary_writer<basic_json, CharType>;
 
   JSON_PRIVATE_UNLESS_TESTED:
@@ -219,6 +219,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     /// the allocator type
     using allocator_type = AllocatorType<basic_json>;
     using allocator_type_ptr = AllocatorType<basic_json*>;
+    using allocator_type_char = AllocatorType<char>;
     /// the type of an element pointer
     using pointer = typename std::allocator_traits<allocator_type>::pointer;
     /// the type of an element const pointer
@@ -4087,7 +4088,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = detail::input_adapter(std::forward<InputType>(i));
         return format == input_format_t::json
                ? parser(std::move(ia), nullptr, true, ignore_comments).sax_parse(sax, strict)
-               : detail::binary_reader<basic_json, decltype(ia), allocator_type_ptr, SAX>(std::move(ia), format).sax_parse(format, sax, strict);
+               : detail::binary_reader<basic_json, decltype(ia), allocator_type_ptr, allocator_type_char, SAX>(std::move(ia), format).sax_parse(format, sax, strict);
     }
 
     /// @brief generate SAX events
@@ -4102,7 +4103,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         auto ia = detail::input_adapter(std::move(first), std::move(last));
         return format == input_format_t::json
                ? parser(std::move(ia), nullptr, true, ignore_comments).sax_parse(sax, strict)
-               : detail::binary_reader<basic_json, decltype(ia), allocator_type_ptr, SAX>(std::move(ia), format).sax_parse(format, sax, strict);
+               : detail::binary_reader<basic_json, decltype(ia), allocator_type_ptr, allocator_type_char, SAX>(std::move(ia), format).sax_parse(format, sax, strict);
     }
 
     /// @brief generate SAX events
@@ -4123,7 +4124,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
                // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
                ? parser(std::move(ia), nullptr, true, ignore_comments).sax_parse(sax, strict)
                // NOLINTNEXTLINE(hicpp-move-const-arg,performance-move-const-arg)
-               : detail::binary_reader<basic_json, decltype(ia), allocator_type_ptr, SAX>(std::move(ia), format).sax_parse(format, sax, strict);
+               : detail::binary_reader<basic_json, decltype(ia), allocator_type_ptr, allocator_type_char, SAX>(std::move(ia), format).sax_parse(format, sax, strict);
     }
 #ifndef JSON_NO_IO
     /// @brief deserialize from stream