diff --git a/include/nlohmann/detail/json_pointer.hpp b/include/nlohmann/detail/json_pointer.hpp
index 3f69bcdf1..84d92c12f 100644
--- a/include/nlohmann/detail/json_pointer.hpp
+++ b/include/nlohmann/detail/json_pointer.hpp
@@ -230,7 +230,7 @@ class json_pointer
         const char* p = s.c_str();
         char* p_end = nullptr;
         errno = 0; // strtoull doesn't reset errno
-        unsigned long long res = std::strtoull(p, &p_end, 10); // NOLINT(runtime/int)
+        const unsigned long long res = std::strtoull(p, &p_end, 10); // NOLINT(runtime/int)
         if (p == p_end // invalid input or empty string
                 || errno == ERANGE // out of range
                 || JSON_HEDLEY_UNLIKELY(static_cast<std::size_t>(p_end - p) != s.size())) // incomplete read
diff --git a/include/nlohmann/detail/output/serializer.hpp b/include/nlohmann/detail/output/serializer.hpp
index 500fc55ec..a7dab5cd6 100644
--- a/include/nlohmann/detail/output/serializer.hpp
+++ b/include/nlohmann/detail/output/serializer.hpp
@@ -926,7 +926,7 @@ class serializer
                 ? (byte & 0x3fu) | (codep << 6u)
                 : (0xFFu >> type) & (byte);
 
-        std::size_t index = 256u + static_cast<size_t>(state) * 16u + static_cast<size_t>(type);
+        const std::size_t index = 256u + static_cast<size_t>(state) * 16u + static_cast<size_t>(type);
         JSON_ASSERT(index < 400);
         state = utf8d[index];
         return state;
diff --git a/single_include/nlohmann/json.hpp b/single_include/nlohmann/json.hpp
index 442a31a7d..342fc0958 100644
--- a/single_include/nlohmann/json.hpp
+++ b/single_include/nlohmann/json.hpp
@@ -13949,7 +13949,7 @@ class json_pointer
         const char* p = s.c_str();
         char* p_end = nullptr;
         errno = 0; // strtoull doesn't reset errno
-        unsigned long long res = std::strtoull(p, &p_end, 10); // NOLINT(runtime/int)
+        const unsigned long long res = std::strtoull(p, &p_end, 10); // NOLINT(runtime/int)
         if (p == p_end // invalid input or empty string
                 || errno == ERANGE // out of range
                 || JSON_HEDLEY_UNLIKELY(static_cast<std::size_t>(p_end - p) != s.size())) // incomplete read
@@ -18848,7 +18848,7 @@ class serializer
                 ? (byte & 0x3fu) | (codep << 6u)
                 : (0xFFu >> type) & (byte);
 
-        std::size_t index = 256u + static_cast<size_t>(state) * 16u + static_cast<size_t>(type);
+        const std::size_t index = 256u + static_cast<size_t>(state) * 16u + static_cast<size_t>(type);
         JSON_ASSERT(index < 400);
         state = utf8d[index];
         return state;
diff --git a/tests/src/unit-allocator.cpp b/tests/src/unit-allocator.cpp
index c6b77ed66..76e3b03f1 100644
--- a/tests/src/unit-allocator.cpp
+++ b/tests/src/unit-allocator.cpp
@@ -159,7 +159,7 @@ TEST_CASE("controlled bad_alloc")
         SECTION("json_value(const string_t&)")
         {
             next_construct_fails = false;
-            my_json::string_t v("foo");
+            const my_json::string_t v("foo");
             CHECK_NOTHROW(my_allocator_clean_up(my_json::json_value(v).string));
             next_construct_fails = true;
             CHECK_THROWS_AS(my_json::json_value(v), std::bad_alloc&);
@@ -172,7 +172,7 @@ TEST_CASE("controlled bad_alloc")
         SECTION("basic_json(const CompatibleObjectType&)")
         {
             next_construct_fails = false;
-            std::map<std::string, std::string> v {{"foo", "bar"}};
+            const std::map<std::string, std::string> v {{"foo", "bar"}};
             CHECK_NOTHROW(my_json(v));
             next_construct_fails = true;
             CHECK_THROWS_AS(my_json(v), std::bad_alloc&);
@@ -182,7 +182,7 @@ TEST_CASE("controlled bad_alloc")
         SECTION("basic_json(const CompatibleArrayType&)")
         {
             next_construct_fails = false;
-            std::vector<std::string> v {"foo", "bar", "baz"};
+            const std::vector<std::string> v {"foo", "bar", "baz"};
             CHECK_NOTHROW(my_json(v));
             next_construct_fails = true;
             CHECK_THROWS_AS(my_json(v), std::bad_alloc&);
@@ -201,7 +201,7 @@ TEST_CASE("controlled bad_alloc")
         SECTION("basic_json(const typename string_t::value_type*)")
         {
             next_construct_fails = false;
-            std::string s("foo");
+            const std::string s("foo");
             CHECK_NOTHROW(my_json(s));
             next_construct_fails = true;
             CHECK_THROWS_AS(my_json(s), std::bad_alloc&);
diff --git a/tests/src/unit-alt-string.cpp b/tests/src/unit-alt-string.cpp
index 609b5d159..291c0ad5f 100644
--- a/tests/src/unit-alt-string.cpp
+++ b/tests/src/unit-alt-string.cpp
@@ -148,7 +148,7 @@ class alt_string
 
     alt_string substr(std::size_t pos = 0, std::size_t count = npos) const
     {
-        std::string s = str_impl.substr(pos, count);
+        const std::string s = str_impl.substr(pos, count);
         return {s.data(), s.size()};
     }