diff --git a/redbeat/schedulers.py b/redbeat/schedulers.py
index 6fcbec7..72c9f4f 100644
--- a/redbeat/schedulers.py
+++ b/redbeat/schedulers.py
@@ -5,7 +5,7 @@
 
 
 from datetime import datetime
-import time
+import calendar
 
 try:
     import simplejson as json
@@ -15,7 +15,7 @@
 from celery.beat import Scheduler, ScheduleEntry
 from celery.utils.log import get_logger
 from celery.signals import beat_init
-from celery.utils.timeutils import humanize_seconds
+from celery.utils.timeutils import humanize_seconds, maybe_make_aware
 from celery.app import app_or_default
 
 from redis.client import StrictRedis
@@ -54,7 +54,11 @@ def redis(app=None):
 
 
 def to_timestamp(dt):
-    return time.mktime(dt.timetuple())
+    return calendar.timegm(maybe_make_aware(dt).timetuple())
+
+
+def from_timestamp(ts):
+    return datetime.utcfromtimestamp(ts)
 
 
 class RedBeatSchedulerEntry(ScheduleEntry):
diff --git a/tests/basecase.py b/tests/basecase.py
index f3f9787..cd20a48 100644
--- a/tests/basecase.py
+++ b/tests/basecase.py
@@ -17,7 +17,7 @@ def setup(self):
         self.app.redbeat_redis = FakeStrictRedis()
         self.app.redbeat_redis.flushdb()
 
-    def create_entry(self, name=None, task=None, s=None, **kwargs):
+    def create_entry(self, name=None, task=None, s=None, run_every=60, **kwargs):
 
         if name is None:
             name = 'test'
@@ -26,7 +26,7 @@ def create_entry(self, name=None, task=None, s=None, **kwargs):
             task = 'tasks.test'
 
         if s is None:
-            s = schedule(run_every=60)
+            s = schedule(run_every=run_every)
 
         e = RedBeatSchedulerEntry(name, task, s, app=self.app, **kwargs)
 
diff --git a/tests/test_entry.py b/tests/test_entry.py
index c1bcd22..289760b 100644
--- a/tests/test_entry.py
+++ b/tests/test_entry.py
@@ -5,6 +5,7 @@
 
 from redbeat import RedBeatSchedulerEntry
 from redbeat.decoder import RedBeatJSONDecoder, RedBeatJSONEncoder
+from redbeat.schedulers import to_timestamp, from_timestamp
 
 
 class test_RedBeatEntry(RedBeatCase):
@@ -110,3 +111,15 @@ def test_due_at_overdue(self):
 
         self.assertLess(last_run_at, due_at)
         self.assertGreater(due_at, before)
+
+    def test_score(self):
+        run_every = 61*60
+        entry = self.create_entry(run_every=run_every)
+        entry = entry._next_instance()
+
+        score = entry.score
+        expected = entry.last_run_at + timedelta(seconds=run_every)
+        expected = expected.replace(microsecond=0)  # discard microseconds, lost in timestamp
+
+        self.assertEqual(score, to_timestamp(expected))
+        self.assertEqual(expected, from_timestamp(score))
diff --git a/tests/test_utils.py b/tests/test_utils.py
new file mode 100644
index 0000000..20e1f01
--- /dev/null
+++ b/tests/test_utils.py
@@ -0,0 +1,15 @@
+from basecase import RedBeatCase
+from redbeat.schedulers import to_timestamp, from_timestamp
+
+
+class Test_utils(RedBeatCase):
+
+    def test_roundtrip(self):
+        now = self.app.now()
+
+        roundtripped = from_timestamp(to_timestamp(now))
+
+        # we lose microseconds in the roundtrip, so we need to ignore them
+        now = now.replace(microsecond=0)
+
+        self.assertEqual(now, roundtripped)