diff --git a/script/index.coffee b/script/index.coffee
index 50a9f98b14..d37f2d342a 100644
--- a/script/index.coffee
+++ b/script/index.coffee
@@ -31,7 +31,10 @@ api.startOfWeek = api.startOfWeek = (options={}) ->
 
 api.startOfDay = (options={}) ->
   o = sanitizeOptions(options)
-  moment(o.now).startOf('day').add('h', o.dayStart)
+  dayStart = moment(o.now).startOf('day').add('h', o.dayStart)
+  # if between midnight and Custom Day Start, jump back to previous day
+  dayStart.subtract('day', 1) if moment(o.now).isBefore(dayStart)
+  return dayStart
 
 dayMapping = {0:'su',1:'m',2:'t',3:'w',4:'th',5:'f',6:'s'}
 
@@ -1239,4 +1242,3 @@ api.wrap = (user, main=true) ->
     get: ->
       tasks = user.habits.concat(user.dailys).concat(user.todos).concat(user.rewards)
       _.object(_.pluck(tasks, "id"), tasks)
-
diff --git a/tests/algos.mocha.coffee b/tests/algos.mocha.coffee
index a86a5f6301..94178e890b 100644
--- a/tests/algos.mocha.coffee
+++ b/tests/algos.mocha.coffee
@@ -487,6 +487,8 @@ describe 'Helper', ->
     expect(shared.startOfDay({now: new Date(2013, 0, 1, 0)}).format('YYYY-MM-DD HH:mm')).to.eql '2013-01-01 00:00'
     expect(shared.startOfDay({now: new Date(2013, 0, 1, 5)}).format('YYYY-MM-DD HH:mm')).to.eql '2013-01-01 00:00'
     expect(shared.startOfDay({now: new Date(2013, 0, 1, 23, 59, 59)}).format('YYYY-MM-DD HH:mm')).to.eql '2013-01-01 00:00'
+    # between midnight and custom day start
+    expect(shared.startOfDay({now: new Date(2013, 0, 2, 2), dayStart: 4}).format('YYYY-MM-DD HH:mm')).to.eql '2013-01-01 04:00'
 
   it 'counts pets', ->
     pets = {}