title: Working with time DURATION, not time of day
body: <p>I'm doing some benchmarking, and I want to use Excel to produce graphs of the results. I've got a simple but annoying problem which is baking my noodle.</p>
  
  <p>The problem is that Excel <em>insists</em> that "time" means a time of day. It refuses to let me work with time <em>durations</em>. When I try to say "three minutes and six seconds", it misinterprets this as "three minutes and six seconds <em>past midnight</em>", which isn't what I meant at all.</p>
  
  <p>I can work around the problem by laboriously converting everything to seconds. But then all my graphs are labelled in seconds, not minutes and seconds. Plus it's a pain to have to keep typing in <code>=3*60+6</code> rather than just <code>3:06</code>. And once I've done it, I have to look at the formula to check whether I entered the data correctly [and didn't screw up the formula].</p>
  
  <p>Does anybody know how I can make Excel work with a time <em>duration</em> not anchored to a specific time of day?</p>