1. Find a flat surface: Choose a level and flat surface that is large enough to fit your luggage. This will make it easy to get accurate measurements.

2. Clear the space: Remove any objects from the area where you’ll be measuring your luggage, which will help prevent interruptions or interference while taking measurements.

3. Use a tape measure: A tape measure is the most suitable tool for measuring luggage as it easily conforms to different shapes and sizes.

4. Measure the height of your luggage: Place your luggage in an upright position. Start measuring from the bottom of the wheel or any protrusions at the base up to the top handle when it’s retracted; this will give you its height.

5. Measure the width of your luggage: To get the width, measure from one side of your luggage to the other, taking into account any side handles or pockets. If your luggage has protruding wheels, make sure to include them in your measurement.

6. Measure the depth (thickness) of your luggage: For obtaining the depth, measure from front to back at its widest point, considering front pockets or any zippers that might cause an increase in thickness.

7. Combine linear dimensions: Add up all three measurements (height, width, and depth) – this is your bag’s linear dimension which is often used by airlines to determine whether a bag meets their size restrictions.

8. Verify airline requirements: Before packing for a trip, check with your airline for their baggage size allowance as these policies vary between carriers and could lead to unwanted fees if not followed correctly.

9. Weigh your empty luggage: In addition to size, airlines may also have weight limits for checked and carry-on bags. Knowing the weight of empty luggage helps gauge how much more weight you can add without exceeding those limits.

10. Keep a record of measurements and weight: Storing these details on your phone or in your luggage tag ensures you have easy access when needed and can prevent unwanted surprises at the check-in counter.

By following these ten steps, you can accurately measure and be prepared for any luggage restrictions that may arise during your travels.