Next, take each item and place it on the scale. Heavier items can be weighed in ounces; items that weigh an ounce or less, I recommend weighing in grams to get a more accurate number. Remember, grams become ounces and ounces can quickly become pounds. As you weigh the item, tabulate a gear list and include the weight. I'm an engineer so, of course, mine is more complicated than most and is put together in an excel spreadsheet.
Well, that's it. Pretty simple step, but you shouldn't underestimate the value of this process. It's important as a UL hiker that you become attuned with every ounce in your pack. It will help you make efficiency values for weight-to-use ratio. This can help you decide which items need replacing and which items need to be eliminated altogether. When you start the transformation to UL hiking, you will be amazed to find how much stuff you've been carrying that you don't need.
Bonus Tip: When I first started hiking, my longtime friend, Frog (and person that sparked my backpacking interest), gave me a valuable tip after my first multi-day trip in the Great Smoky Mountains. He said, "When you get home, unpack your pack into two piles. Pile one-stuff you used, pile two-stuff you didn't. Put the first pile with your backpacking gear and sell the second pile to some sucker on craigslist." In Frog's own words, he is saying eliminate non essentials, which is basically the take home message from this post