diff --git a/include/nlohmann/detail/output/binary_writer.hpp b/include/nlohmann/detail/output/binary_writer.hpp
index 8a172056b..cbe6e5617 100644
--- a/include/nlohmann/detail/output/binary_writer.hpp
+++ b/include/nlohmann/detail/output/binary_writer.hpp
@@ -282,8 +282,26 @@ class binary_writer
             {
                 if (j.m_value.binary->has_subtype())
                 {
-                    write_number(static_cast<std::uint8_t>(0xd8));
-                    write_number(j.m_value.binary->subtype());
+                    if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint8_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xd8));
+                        write_number(static_cast<std::uint8_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint16_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xd9));
+                        write_number(static_cast<std::uint16_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint32_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xda));
+                        write_number(static_cast<std::uint32_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint64_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xdb));
+                        write_number(static_cast<std::uint64_t>(j.m_value.binary->subtype()));
+                    }
                 }
 
                 // step 1: write control byte and the binary array size
@@ -1096,7 +1114,7 @@ class binary_writer
         write_bson_entry_header(name, 0x05);
 
         write_number<std::int32_t, true>(static_cast<std::int32_t>(value.size()));
-        write_number(value.has_subtype() ? value.subtype() : std::uint8_t(0x00));
+        write_number(value.has_subtype() ? static_cast<std::uint8_t>(value.subtype()) : std::uint8_t(0x00));
 
         oa->write_characters(reinterpret_cast<const CharType*>(value.data()), value.size());
     }
diff --git a/include/nlohmann/json.hpp b/include/nlohmann/json.hpp
index cd8152811..43dc1d9d8 100644
--- a/include/nlohmann/json.hpp
+++ b/include/nlohmann/json.hpp
@@ -1817,7 +1817,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     @since version 3.8.0
     */
     JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json binary(const typename binary_t::container_type& init, std::uint8_t subtype)
+    static basic_json binary(const typename binary_t::container_type& init, typename binary_t::subtype_type subtype)
     {
         auto res = basic_json();
         res.m_type = value_t::binary;
@@ -1835,9 +1835,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res;
     }
 
-    /// @copydoc binary(const typename binary_t::container_type&, std::uint8_t)
+    /// @copydoc binary(const typename binary_t::container_type&, typename binary_t::subtype_type)
     JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json binary(typename binary_t::container_type&& init, std::uint8_t subtype)
+    static basic_json binary(typename binary_t::container_type&& init, typename binary_t::subtype_type subtype)
     {
         auto res = basic_json();
         res.m_type = value_t::binary;
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 1f557450c..1d69fb63f 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -13585,8 +13585,26 @@ class binary_writer
             {
                 if (j.m_value.binary->has_subtype())
                 {
-                    write_number(static_cast<std::uint8_t>(0xd8));
-                    write_number(j.m_value.binary->subtype());
+                    if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint8_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xd8));
+                        write_number(static_cast<std::uint8_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint16_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xd9));
+                        write_number(static_cast<std::uint16_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint32_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xda));
+                        write_number(static_cast<std::uint32_t>(j.m_value.binary->subtype()));
+                    }
+                    else if (j.m_value.binary->subtype() <= (std::numeric_limits<std::uint64_t>::max)())
+                    {
+                        write_number(static_cast<std::uint8_t>(0xdb));
+                        write_number(static_cast<std::uint64_t>(j.m_value.binary->subtype()));
+                    }
                 }
 
                 // step 1: write control byte and the binary array size
@@ -14399,7 +14417,7 @@ class binary_writer
         write_bson_entry_header(name, 0x05);
 
         write_number<std::int32_t, true>(static_cast<std::int32_t>(value.size()));
-        write_number(value.has_subtype() ? value.subtype() : std::uint8_t(0x00));
+        write_number(value.has_subtype() ? static_cast<std::uint8_t>(value.subtype()) : std::uint8_t(0x00));
 
         oa->write_characters(reinterpret_cast<const CharType*>(value.data()), value.size());
     }
@@ -18911,7 +18929,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
     @since version 3.8.0
     */
     JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json binary(const typename binary_t::container_type& init, std::uint8_t subtype)
+    static basic_json binary(const typename binary_t::container_type& init, typename binary_t::subtype_type subtype)
     {
         auto res = basic_json();
         res.m_type = value_t::binary;
@@ -18929,9 +18947,9 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
         return res;
     }
 
-    /// @copydoc binary(const typename binary_t::container_type&, std::uint8_t)
+    /// @copydoc binary(const typename binary_t::container_type&, typename binary_t::subtype_type)
     JSON_HEDLEY_WARN_UNUSED_RESULT
-    static basic_json binary(typename binary_t::container_type&& init, std::uint8_t subtype)
+    static basic_json binary(typename binary_t::container_type&& init, typename binary_t::subtype_type subtype)
     {
         auto res = basic_json();
         res.m_type = value_t::binary;