If you’re a procrastinator, you don’t need a mathematical formula, you know who you are. Worse, the people who work with you know, too. I’ve tried the “set the clock ahead 10 minutes” trick, but it never works because I know that I really have that extra 10 minutes. If you’re nodding, then perhaps you need David Seah’s Procrastinator’s Clock.
It’s guaranteed to be up to 15 minutes fast. However, it also speeds up and slows down in an unpredictable manner so you can’t be sure how fast it really is. Furthermore, the clock is guaranteed not be slow, assuming your computer clock is sync’d with NTP; many computers running Windows and Mac OS X with persistent Internet connections already are.