diff --git a/oauth3.core.js b/oauth3.core.js
index 825a882..b4385fd 100644
--- a/oauth3.core.js
+++ b/oauth3.core.js
@@ -224,20 +224,27 @@
 
         return OAUTH3.crypto.core.verify(jwk, data, signature);
       }
-    , freshness: function (tokenMeta, staletime, _now) {
-        staletime = staletime || (15 * 60);
-        var now = _now || Date.now();
-        var fresh = ((parseInt(tokenMeta.exp, 10) || 0) - Math.round(now / 1000));
-
-        if (fresh >= staletime) {
+    , freshness: function (tokenMeta, staletime, now) {
+        // If the token doesn't expire then it's always fresh.
+        if (!tokenMeta.exp) {
           return 'fresh';
         }
 
-        if (fresh <= 0) {
-          return 'expired';
+        staletime = staletime || (15 * 60);
+        now = now || Date.now();
+        // This particular number used to check if time is in milliseconds or seconds will work
+        // for any date between the years 1973 and 5138.
+        if (now > 1e11) {
+          now = Math.round(now / 1000);
+        }
+        var exp = parseInt(tokenMeta.exp, 10) || 0;
+        if (exp < now) {
+          return 'expired';
+        } else if (exp < now + staletime) {
+          return 'stale';
+        } else {
+          return 'fresh';
         }
-
-        return 'stale';
       }
     }
   , urls: {