title: Excel working time calculation
body: <p>I am trying to put together an excel spreadsheet to track working time. A standard working day is say 8 hours with one hour lunch, say 40 hours total, 35 hours working. I need to track over and under time on a given day, and total this for a week period. The reason is to that if someone only takes a 30 minute lunch for three days, they can then take 1.5 hours off early at the end of the week for example.</p>
  
  <p>Example daily record:</p>
  
  
  
  <pre><code>Mon - 9-6, 1 hour lunch = 8 working hours, 1 hour lunch, balance = 0 (the perfect day)
  Tue - 8-6, 1 hour lunch = 9 working hours, 1 hour lunch, balance = +60 (one hour over)
  Wed - 9-4, 1 hour lunch = 7 working hours, 1 hour lunch, balance = -60 (one hour under)
  Thu - 9-6, 30 min lunch = 8 working hours, 30 min lunch, balance = +30 (30 mins over)
  Fri - 9-6, 30 min lunch = 8 working hours, 30 min lunch, balance = +30 (30 mins over)
  </code></pre>
  
  <p>Example end of week totals</p>
  
  <p>I am recording start/end/lunch times in excel in custom "time format" cells: 09:00 - 17:00
  I am getting the hours with this formula: =TEXT(End-Start,"hh:mm")
  I enter the lunch time in "time format" 00:30 (30 mins)
  I get the actual time worked  with this formula: =TEXT(Total-Lunch,"hh:mm")</p>
  
  <p>When I try to add together / sum the values however I am not getting anything...</p>
  
  <p>Any thoughts?</p>