This may be one of the simpler questions on the Common App, but I literally have no idea how to answer it. I’m a leader of several student-led organisations, but it’s hard for me to gauge how many hours I spend working on/with a particular organisation every week. There are some weeks where I work >10 hours (especially before big events) and others where I work less <1 hour. How do I put it down as a single number on the Common App? I don’t want to lie
A wild guess is fine. Details like this aren’t scrutinized-- nor even much considered. Maybe over a semester of 20 wks, you performed 30 hours of svc. Then write 1.5 hrs/week or 60 hrs/year.
It’s designed to be an estimate, unless you keep a meticulous log.
Don’t keep a meticulous log.
@T26E4 I wasn’t suggesting they keep a meticulous log. However, I do know certain school clubs keep record logs, which a student could reference to count hours (for example, student government and the newspaper at my school keep logs).
Yes, just put an average—your best guess.
Thanks all 
A best guess is fine, as long as there is some simple logic behind it as @T26E4 mentioned above. But make sure to make a note of your logic just in case you are ever asked about it (which is unlikely).