diff --git a/waybackpy/wrapper.py b/waybackpy/wrapper.py
index 7a69475..4b4296d 100644
--- a/waybackpy/wrapper.py
+++ b/waybackpy/wrapper.py
@@ -36,9 +36,11 @@ def _archive_url_parser(header):
     )
 
 
-def _wayback_timestamp(dt):
+def _wayback_timestamp(**kwargs):
     """Return a formatted timestamp."""
-    return dt.strftime("%Y%m%d%h%m")
+    return "".join(
+        str(kwargs[key]).zfill(2) for key in ["year", "month", "day", "hour", "minute"]
+    )
 
 
 class Url:
@@ -111,14 +113,14 @@ class Url:
         Supported params are year, month, day, hour and minute.
         Any non-supplied parameters default to the current time.
         """
-        kwargs = {
-            key: val
-            for key, val in dict(
-                year=year, month=month, day=day, hour=hour, minute=minute
-            )
-            if val is not None
-        }
-        timestamp = _wayback_timestamp(datetime.utcnow().replace(**kwargs))
+        now = datetime.utcnow().timetuple()
+        timestamp = _wayback_timestamp(
+            year=year if year else now.tm_year,
+            month=month if month else now.tm_mon,
+            day=day if day else now.tm_mday,
+            hour=hour if hour else now.tm_hour,
+            minute=minute if minute else now.tm_min,
+        )
 
         request_url = "https://archive.org/wayback/available?url=%s&timestamp=%s" % (
             self._clean_url(),