Should you turn off the fluorescent light or not?  
 
You sometimes hear people say that you should not turn off fluorescent lights for short periods, because the energy it takes to restrike the lamp exceeds what you save. But exactly how "short" is the break-even absence?

Try various assumptions below.
 
Enter your assumptions for:  
  Lamp power: W    
  Peak surge: times normal current
  Surge duration: millisecond
         
Conclusion:    
 
Rationale: the break-even absence is how long the lamp would have to run, at normal power, to equal the energy consumed during the surge. One millisecond at 20 times normal current, for example, equals 20 ms of normal running.