Does your trip have a weight limit? Not you of course. I was referring to your luggage. If so, buy a scale, one with a hook or strap to hang luggage from and you can easily see what it weighs.
On our last trip we had to take a small, chartered plane for one of the legs with a weight limit of 33lbs per each of 2 suitcases. I was so worried about this, because you know how you can stuff a suitcase, that I purchased a hand luggage scale. Now I was set.
When we arrived at the airport, our luggage had to be weighed for the airline's purposes - to see if we are over their weight limit. All of a sudden, my luggage weighed 51 pounds. Now, unless I had someone else's suitcase, I have no idea how that happened. My guess is that the scales at the airlines may be wrong. Maybe it is a case of not being checked often enough or...do they do it on purpose? I have no idea, but this is reason enough to purchase these small scales for a do it yourself check. I weighed my luggage numerous times just to be certain I was reading it correctly. I know I was right and the airline was wrong. (I was not over the airline's weight limit, so I didn't bother to complain that day.)
Have a great trip!
Where to buy: I purchased a luggage scale from LLBean.com. It was easy to use so I was able to pack properly. The exact one I purchased is not on the site but they have one called "Balanzza Luggage Scale Ergo" at $25. You can also find others which cost less, at Magellans.com, for example, which has one similar to what I have for $9.95, item # KT689.