diff --git a/include/json.h b/include/json.h
index 3706034fd..27e621ebb 100644
--- a/include/json.h
+++ b/include/json.h
@@ -262,6 +262,11 @@ namespace crow
                 return i();
             }
 
+            explicit operator uint64_t() const
+            {
+                return u();
+            }
+
             explicit operator int() const
             {
                 return (int)i();
@@ -294,6 +299,20 @@ namespace crow
                 return boost::lexical_cast<int64_t>(start_, end_-start_);
             }
 
+            uint64_t u() const
+            {
+#ifndef CROW_JSON_NO_ERROR_CHECK
+                switch (t()) {
+                    case type::Number:
+                    case type::String:
+                        return boost::lexical_cast<uint64_t>(start_, end_-start_);
+                    default:
+                        throw std::runtime_error(std::string("expected number, got: ") + get_type_str(t()));
+                }
+#endif
+                return boost::lexical_cast<uint64_t>(start_, end_-start_);
+            }
+
             double d() const
             {
 #ifndef CROW_JSON_NO_ERROR_CHECK
@@ -1289,7 +1308,7 @@ namespace crow
                     o = std::unique_ptr<
                                 std::unordered_map<std::string, wvalue>
                             >(
-                            new std::unordered_map<std::string, wvalue>{}));
+                            new std::unordered_map<std::string, wvalue>{});
                 return (*o)[str];
             }
 
diff --git a/tests/unittest.cpp b/tests/unittest.cpp
index 9021af5e1..78732b090 100644
--- a/tests/unittest.cpp
+++ b/tests/unittest.cpp
@@ -519,6 +519,10 @@ TEST(json_read)
     ASSERT_EQUAL(false, z["bools"][1].b());
     ASSERT_EQUAL(1.2, z["doubles"][0].d());
     ASSERT_EQUAL(-3.4, z["doubles"][1].d());
+
+    std::string s3 = R"({"uint64": 18446744073709551615})";
+    auto z1 = json::load(s3);
+    ASSERT_EQUAL(18446744073709551615ull, z1["uint64"].u());
 }
 
 TEST(json_read_real)