diff --git a/include/chaiscript/utility/json.hpp b/include/chaiscript/utility/json.hpp
index 6fe2e58..676b469 100644
--- a/include/chaiscript/utility/json.hpp
+++ b/include/chaiscript/utility/json.hpp
@@ -569,13 +569,15 @@ struct JSONParser {
     bool isDouble = false;
     bool isNegative = false;
     long exp = 0;
+    if( offset < str.size() && str[offset] == '-' ) {
+      isNegative = true;
+      ++offset;
+    }
     for (; offset < str.size() ;) {
       c = str[offset++];
-      if( c == '-' ) {
-        isNegative = true;
-      } else if( c >= '0' && c <= '9' ) {
+      if( c >= '0' && c <= '9' ) {
         val += c;
-      } else if( c == '.' ) {
+      } else if( c == '.' && !isDouble ) {
         val += c; 
         isDouble = true;
       } else {
diff --git a/unittests/json_4.chai b/unittests/json_4.chai
index 34ecfa9..ae07024 100644
--- a/unittests/json_4.chai
+++ b/unittests/json_4.chai
@@ -1,2 +1,22 @@
 assert_equal(from_json("1.234"), 1.234)
 assert_equal(from_json("-1.234"), -1.234)
+
+auto caught = false;
+try {
+  from_json("-1-5.3");
+}
+catch(e) {
+  assert_equal("JSON ERROR: Number: unexpected character '-'", e.what());
+  caught = true;
+}
+assert_equal(caught, true);
+
+caught = false;
+try {
+  from_json("-15.3.2");
+}
+catch(e) {
+  assert_equal("JSON ERROR: Number: unexpected character '.'", e.what());
+  caught = true;
+}
+assert_equal(caught, true);