Leveling the bottom kitchen cabinets well will ensure that your counter tops remain level and any hanging kitchen cabinets are parallel to the other cabinets as well as the floor. While the technique used to level the bottom kitchen cabinets is not difficult, it may require some time to get everything perfectly level. For this reason, an assistant that can help move the cabinets and check the level while you are otherwise occupied is invaluable.
Step 1: Connect all of the base cabinets, or bottom kitchen cabinets, until they are flush in front. This will allow you to level all of the cabinets as one complete unit, which will make your project even easier.
Step 2: Push the kitchen cabinets into place if they are not already in the installation location.
Step 3: Put the level on the top of the cabinets, and check the bubble inside the level. The bubble should fit neatly between the lines, indicating that the cabinets are completely level. Be sure to check the level side to side as well as front to back.
TIP: A long level will give you results that are the most accurate. The minimum is a 3 foot level for accurate results, but a 4 foot level is preferable.
Step 4: If your level indicates that the cabinets are not level, have a friend lift the edge of the cabinets with a crow bar. Slide a thin wooden shim underneath the gap to level the kitchen cabinets. Start with the back if you need to, this will be the hardest area to level
Step 5: Continue adding shims, or pulling out shims until the kitchen cabinets are completely level.
Step 6: Screw through the mounting strips and into the studs beneath the drywall. Check the kitchen cabinets with the level once more to make sure that they have not shifted.
Step 7: Saw off the shims so they are flush with the cabinets.
Step 8: Install baseboards or other trim to conceal any shims you used in the front section of the kitchen cabinets.