The last Scribe in a technology ruled false utopian future must unite with an android that contains the entirety of human history, before the ruling corporation can enact their final technological control onto the masses.

Also not to forget that a logline can fulfil two goals for the writer.

The first is structuring tool that helps you boiled down your concept to its bare minimum mission critical elements of the story. This helps you test your concept and see if it is worth spending months on end developing and writing.

The second is a pitching tool that helps you communicate in the most efficient way to others what your concept is. This is what the others have described above.

You need to know which function your logline needs to fulfil and draft it accordingly. In either event less is more of course, but when you need to hook the interest of an over worked executive (who wants to know that you are professional enough to be aware of the pressure he or she is under) the word count is more critical. Drop anything that is not crucial for them to understand.

If you are trying to test and re work your concept then the word count is less important.

Lastly about the logline I will add to what the others have posted that the starting point of your story is unclear. Why now? What makes the scribe need to take action at this crucial point in time?

Hope this helps.

There's no hard rule. Only guidelines. Thirty words seems to be the conventional wisdom. How this wisdom was arrived it and by whom, I know not.

So I put the conventional wisdom to a test. I collected and analyzed 600 randomly chosen loglines of scripts that survived the green light gauntlet and actually got made into films. The median length for the sample was 23 words. Nearly 87% of the loglines were 30 words or less. None of them in my sample exceeded 40 words. So I take 40 words I take as my tolerable limit.

The madness behind the measure of an arbitrary maximum length is the presumption that studio suits are busy people facing scores of loglines per day fighting for quality eye ball time. A logline has only a precious few seconds to get it. Ergo, less (aka: "high concept") is almost always better than more.

My takeaway from crunching hard numbers: while not everyone will agree with the presumption or the conventional wisdom, I see no reason not to.

fwiw

Hi Davron, there are no rules about length of loglines as such. If you visit the 'Go Into The Story' website they have the official studio loglines for scripts bought from first-time writers over the last 7 years. You'll find loglines with over 100 words.