Does anybody know...

... how much a barbell alone weighs?

When people say "I deadlift 150 pounds" or "I benchpress 125 pounds", do they include the weight of the barbell or only the weight of the plates that they add?

Just curious...

Thanks!

Weight of the barbell plus the plates.

An olympic bar weighs 45lb - at least that's how much mine weighs.

I read conflicting info on internet. Some says it weighs 20 lbs, other says 45 lbs.

What's the difference between an olympic bar and a "regular" one? How do I know which one they have at my gym?

There might be a difference in length, but I think diameter is the main difference - olympic bars are thicker - over an inch, I'd say, while regular bars have a diameter of less than an inch?

It depends on the type of bar. If it's an "Olympic" bar (the standard in most gyms -- and the kind with the large collar) ... it's 45 pounds, as amethysgirl says. The "large" weights are Olympic weights will be 45 pounds and very often designated in kilograms, as well - 20.4, like this --

http://www.fitnessscape.com/Merchant2/graphic s/00000002/cap-barbell-OPG-olympic-weights-s. jpg

So, a bar with two 45-pound weights on it would be 135 pounds (45+45+45).

Here's a picture of Olympic weights -

http://www.robbinssports.com/sporting-goods-s tore/images/300-Lb.-Deluxe-Weight-Set.jpg

If your weight set doesn't look like that, then it is another kind ... and very likely has a lighter bar. 

As for calculating the weight that one is lifting ... you add in everything. So, you would add the weight of the plates, the weight of the bar, the weight of the your sweat and tears on the bar  ... everything!

Everyone is correct about adding in the weight of the bar plus the plates for total weight.  One thing you might should know which may be or may not be important to you is that the Olympic bar is actually closer to 42 lbs. everyone just rounds it up to 45.  So when you have 2 45 lb plates and the bar it is actually 132 lbs., but everyone just says 135.  Don't know if that matters to you or not just thought I would add that in.

Thanks everyone!

I looked on wiki: http://en.wikipedia.org/wiki/Barbell

The article talks in great lengths about the olympic barbell, which is 44.1 lbs apparently, and at the end mentions the standard barbell, which is 22 lbs. When I looked in Google image they all looked the same to me! I guess I'm just gonna ask my gym. I hope the barbells are 45 lbs because it would means I squat 90 lbs. Not bad for a beginner