Look at your airlines website for its baggage requirements. It will state the total size and weight it can be. Most flights within the United States allow bags to be up to a total of 62 inches and no heaver than 50 pounds.
Pack your bag complete and lay it flat on the floor or a table.
Measure the top of the bag from top to bottom. This is the width of the bag. Write the number down on a piece of paper.
Measure the top of the bag from left to right. This is the length of the bag. Write the number down on a piece of paper.
Measure the side of the bag from top to bottom. This is the height of the bag. Write the number down on a piece of paper.
Add up the three numbers. If they are less than the total number of inches allowed, the size of your bag is good to go.
Step on your home scale until it displays your weight.
Write down your weight on a piece of paper.
Pick up your bag and step back onto the scale, making sure the bag is not touching the ground.
Write down the total weight of you and the bag.
Remove articles if necessary to stay under the airline baggage weight limit. If your bag was lighter then your bag is all set for air travel.