Moderate, light, sedentary? Huh?

OK, I am a graduate student which means that I sit on my butt a lot at least a few hours a day to read things and attend class. However, I have no car so I walk and awful lot. I estimate that I ascend and descend about 6 flights of stairs a day...at least. And I have to walk a few blocks just to get to the metro station to get to class, if I can walk somewhere I do, grocery store, class, to the opera....etc.

I listed myself as light activity, because at my preivous job, as a UPS delivery driver I was constantly moving(worked an industrial route) and now I feel like even with the running and walikng I am doing near nothing everyday.

I am also running about 45-30 minutes a day and doing a light 45 minute pilates workout (nothing too strenuous) maybe once or twice a week. But I log in those as separate.

What should be my base rating, light or moderate or what?

Welcome to cc!

I think the easiest and most accurate method is to classify yourself as sedentary (light) and add your exercise activities as you go. I myself only add actual exercise (ie walking for extended time or distance, elliptical, treadmill, etc) and other activities requiring some effort (ie shovelling snow). 

Edit:  just read your profile and noticed you are in Czech - land of the chocolate breakfasts!  My babysitter who was with us for years was Czech and was such a caring, loving person - happy and optomistic.  She left us to return home and I still miss her (my sons are now in their mid-teens!)  One thing I do know is that it is customary to purchase your food more or less on a daily basis which is good for assuring you have fresh fruits, vegetables and meats!  In North America we rely (I think) too much on canned and prepared foods and this can be quite an adjustment for someone moving here from abroad.

What I did (and still do), and typically recommend, is to go with the Sedentary at first.  As you do an activity, log it.

Everyone's interpretation of light, moderate and such can differ.  You want to get as accurate a picture as possible.  So best bet is for the first month at least, log in all activities while on Sedentary.  You can then look back at a month's history and see if you should rethink your setting to be at light.

My exercise routine can vary.  Things happen and I sometimes skip or do more than I normally do.  I can also do things with a higher intensity or a lower intensity depending on how I am feeling.

Basically, there are so many factors invovled in determining the level, I prefer to just decide on the stop.  It doesn't take much time to log it in. 

Actually I would say you're at least light. I gained all my weight as soon as I left college because I wasn't climbing all those steps and walking all over campus. Once I hit the post-graduation world, I sitting at a desk for eight hours straight and maybe once a week hitting the metro parks for an hour long walk. That's sedentary--not someone who runs every day.
If you undercut your calories too much, you're going to be even more exhausted than I'm sure you already are as a grad student. I'd say mark yourself as light. I was eating sedntary calories but had added about the same amount of activity you have into my routine--and I was falling asleep at my desk at work and not losing any weight because I wasn't getting enough calories. It's one of the biggest mistakes dieters make. Especially if you are running regularly. You need calories to burn calories.
And if you have a day where all you're doing is studying in front of a stack of books, cut back your intake a little.
I know this is condradicting the last post, but if you DO decide to try the sedentary route, and you don't lose weight, please try the light level. I have seen people on these posts that are near eating disorders because they keep cutting and cutting calories and adding and adding exercise and can't lose weight because they don't understand that you need to eat to match your activity level.